3211 lines
86 KiB
C
3211 lines
86 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
|
|
/* PASST - Plug A Simple Socket Transport
|
|
* for qemu/UNIX domain socket mode
|
|
*
|
|
* PASTA - Pack A Subtle Tap Abstraction
|
|
* for network namespace/tap device mode
|
|
*
|
|
* tcp.c - TCP L2-L4 translation state machine
|
|
*
|
|
* Copyright (c) 2020-2022 Red Hat GmbH
|
|
* Author: Stefano Brivio <sbrivio@redhat.com>
|
|
*/
|
|
|
|
/**
|
|
* DOC: Theory of Operation
|
|
*
|
|
*
|
|
* PASST mode
|
|
* ==========
|
|
*
|
|
* This implementation maps TCP traffic between a single L2 interface (tap) and
|
|
* native TCP (L4) sockets, mimicking and reproducing as closely as possible the
|
|
* inferred behaviour of applications running on a guest, connected via said L2
|
|
* interface. Four connection flows are supported:
|
|
* - from the local host to the guest behind the tap interface:
|
|
* - this is the main use case for proxies in service meshes
|
|
* - we bind to configured local ports, and relay traffic between L4 sockets
|
|
* with local endpoints and the L2 interface
|
|
* - from remote hosts to the guest behind the tap interface:
|
|
* - this might be needed for services that need to be addressed directly,
|
|
* and typically configured with special port forwarding rules (which are
|
|
* not needed here)
|
|
* - we also relay traffic between L4 sockets with remote endpoints and the L2
|
|
* interface
|
|
* - from the guest to the local host:
|
|
* - this is not observed in practice, but implemented for completeness and
|
|
* transparency
|
|
* - from the guest to external hosts:
|
|
* - this might be needed for applications running on the guest that need to
|
|
* directly access internet services (e.g. NTP)
|
|
*
|
|
* Relevant goals are:
|
|
* - transparency: sockets need to behave as if guest applications were running
|
|
* directly on the host. This is achieved by:
|
|
* - avoiding port and address translations whenever possible
|
|
* - mirroring TCP dynamics by observation of socket parameters (TCP_INFO
|
|
* socket option) and TCP headers of packets coming from the tap interface,
|
|
* reapplying those parameters in both flow directions (including TCP_MSS
|
|
* socket option)
|
|
* - simplicity: only a small subset of TCP logic is implemented here and
|
|
* delegated as much as possible to the TCP implementations of guest and host
|
|
* kernel. This is achieved by:
|
|
* - avoiding a complete TCP stack reimplementation, with a modified TCP state
|
|
* machine focused on the translation of observed events instead
|
|
* - mirroring TCP dynamics as described above and hence avoiding the need for
|
|
* segmentation, explicit queueing, and reassembly of segments
|
|
* - security:
|
|
* - no dynamic memory allocation is performed
|
|
* - TODO: synflood protection
|
|
*
|
|
* Portability is limited by usage of Linux-specific socket options.
|
|
*
|
|
*
|
|
* Limits
|
|
* ------
|
|
*
|
|
* To avoid the need for dynamic memory allocation, a maximum, reasonable amount
|
|
* of connections is defined by TCP_MAX_CONNS (currently 128k).
|
|
*
|
|
* Data needs to linger on sockets as long as it's not acknowledged by the
|
|
* guest, and is read using MSG_PEEK into preallocated static buffers sized
|
|
* to the maximum supported window, 16 MiB ("discard" buffer, for already-sent
|
|
* data) plus a number of maximum-MSS-sized buffers. This imposes a practical
|
|
* limitation on window scaling, that is, the maximum factor is 256. Larger
|
|
* factors will be accepted, but resulting, larger values are never advertised
|
|
* to the other side, and not used while queueing data.
|
|
*
|
|
*
|
|
* Ports
|
|
* -----
|
|
*
|
|
* To avoid the need for ad-hoc configuration of port forwarding or allowed
|
|
* ports, listening sockets can be opened and bound to all unbound ports on the
|
|
* host, as far as process capabilities allow. This service needs to be started
|
|
* after any application proxy that needs to bind to local ports. Mapped ports
|
|
* can also be configured explicitly.
|
|
*
|
|
* No port translation is needed for connections initiated remotely or by the
|
|
* local host: source port from socket is reused while establishing connections
|
|
* to the guest.
|
|
*
|
|
* For connections initiated by the guest, it's not possible to force the same
|
|
* source port as connections are established by the host kernel: that's the
|
|
* only port translation needed.
|
|
*
|
|
*
|
|
* Connection tracking and storage
|
|
* -------------------------------
|
|
*
|
|
* Connections are tracked by struct tcp_tap_conn entries in the @tc
|
|
* array, containing addresses, ports, TCP states and parameters. This
|
|
* is statically allocated and indexed by an arbitrary connection
|
|
* number. The array is compacted whenever a connection is closed, by
|
|
* remapping the highest connection index in use to the one freed up.
|
|
*
|
|
* References used for the epoll interface report the connection index used for
|
|
* the @tc array.
|
|
*
|
|
* IPv4 addresses are stored as IPv4-mapped IPv6 addresses to avoid the need for
|
|
* separate data structures depending on the protocol version.
|
|
*
|
|
* - Inbound connection requests (to the guest) are mapped using the triple
|
|
* < source IP address, source port, destination port >
|
|
* - Outbound connection requests (from the guest) are mapped using the triple
|
|
* < destination IP address, destination port, source port >
|
|
* where the source port is the one used by the guest, not the one used by the
|
|
* corresponding host socket
|
|
*
|
|
*
|
|
* Initialisation
|
|
* --------------
|
|
*
|
|
* Up to 2^15 + 2^14 listening sockets (excluding ephemeral ports, repeated for
|
|
* IPv4 and IPv6) can be opened and bound to wildcard addresses. Some will fail
|
|
* to bind (for low ports, or ports already bound, e.g. by a proxy). These are
|
|
* added to the epoll list, with no separate storage.
|
|
*
|
|
*
|
|
* Events and states
|
|
* -----------------
|
|
*
|
|
* Instead of tracking connection states using a state machine, connection
|
|
* events are used to determine state and actions for a given connection. This
|
|
* makes the implementation simpler as most of the relevant tasks deal with
|
|
* reactions to events, rather than state-associated actions. For user
|
|
* convenience, approximate states are mapped in logs from events by
|
|
* @tcp_state_str.
|
|
*
|
|
* The events are:
|
|
*
|
|
* - SOCK_ACCEPTED connection accepted from socket, SYN sent to tap/guest
|
|
*
|
|
* - TAP_SYN_RCVD tap/guest initiated connection, SYN received
|
|
*
|
|
* - TAP_SYN_ACK_SENT SYN, ACK sent to tap/guest, valid for TAP_SYN_RCVD only
|
|
*
|
|
* - ESTABLISHED connection established, the following events are valid:
|
|
*
|
|
* - SOCK_FIN_RCVD FIN (EPOLLRDHUP) received from socket
|
|
*
|
|
* - SOCK_FIN_SENT FIN (write shutdown) sent to socket
|
|
*
|
|
* - TAP_FIN_RCVD FIN received from tap/guest
|
|
*
|
|
* - TAP_FIN_SENT FIN sent to tap/guest
|
|
*
|
|
* - TAP_FIN_ACKED ACK to FIN seen from tap/guest
|
|
*
|
|
* Setting any event in CONN_STATE_BITS (SOCK_ACCEPTED, TAP_SYN_RCVD,
|
|
* ESTABLISHED) clears all the other events, as those represent the fundamental
|
|
* connection states. No events (events == CLOSED) means the connection is
|
|
* closed.
|
|
*
|
|
* Connection setup
|
|
* ----------------
|
|
*
|
|
* - inbound connection (from socket to guest): on accept() from listening
|
|
* socket, the new socket is mapped in connection tracking table, and
|
|
* three-way handshake initiated towards the guest, advertising MSS and window
|
|
* size and scaling from socket parameters
|
|
* - outbound connection (from guest to socket): on SYN segment from guest, a
|
|
* new socket is created and mapped in connection tracking table, setting
|
|
* MSS and window clamping from header and option of the observed SYN segment
|
|
*
|
|
*
|
|
* Aging and timeout
|
|
* -----------------
|
|
*
|
|
* Timeouts are implemented by means of timerfd timers, set based on flags:
|
|
*
|
|
* - SYN_TIMEOUT: if no ACK is received from tap/guest during handshake (flag
|
|
* ACK_FROM_TAP_DUE without ESTABLISHED event) within this time, reset the
|
|
* connection
|
|
*
|
|
* - ACK_TIMEOUT: if no ACK segment was received from tap/guest, after sending
|
|
* data (flag ACK_FROM_TAP_DUE with ESTABLISHED event), re-send data from the
|
|
* socket and reset sequence to what was acknowledged. If this persists for
|
|
* more than TCP_MAX_RETRANS times in a row, reset the connection
|
|
*
|
|
* - FIN_TIMEOUT: if a FIN segment was sent to tap/guest (flag ACK_FROM_TAP_DUE
|
|
* with TAP_FIN_SENT event), and no ACK is received within this time, reset
|
|
* the connection
|
|
*
|
|
* - FIN_TIMEOUT: if a FIN segment was acknowledged by tap/guest and a FIN
|
|
* segment (write shutdown) was sent via socket (events SOCK_FIN_SENT and
|
|
* TAP_FIN_ACKED), but no socket activity is detected from the socket within
|
|
* this time, reset the connection
|
|
*
|
|
* - ACT_TIMEOUT, in the presence of any event: if no activity is detected on
|
|
* either side, the connection is reset
|
|
*
|
|
* - ACK_INTERVAL elapsed after data segment received from tap without having
|
|
* sent an ACK segment, or zero-sized window advertised to tap/guest (flag
|
|
* ACK_TO_TAP_DUE): forcibly check if an ACK segment can be sent
|
|
*
|
|
*
|
|
* Summary of data flows (with ESTABLISHED event)
|
|
* ----------------------------------------------
|
|
*
|
|
* @seq_to_tap: next sequence for packets to tap/guest
|
|
* @seq_ack_from_tap: last ACK number received from tap/guest
|
|
* @seq_from_tap: next sequence for packets from tap/guest (expected)
|
|
* @seq_ack_to_tap: last ACK number sent to tap/guest
|
|
*
|
|
* @seq_init_from_tap: initial sequence number from tap/guest
|
|
* @seq_init_to_tap: initial sequence number from tap/guest
|
|
*
|
|
* @wnd_from_tap: last window size received from tap, never scaled
|
|
* @wnd_from_tap: last window size advertised from tap, never scaled
|
|
*
|
|
* - from socket to tap/guest:
|
|
* - on new data from socket:
|
|
* - peek into buffer
|
|
* - send data to tap/guest:
|
|
* - starting at offset (@seq_to_tap - @seq_ack_from_tap)
|
|
* - in MSS-sized segments
|
|
* - increasing @seq_to_tap at each segment
|
|
* - up to window (until @seq_to_tap - @seq_ack_from_tap <= @wnd_from_tap)
|
|
* - on read error, send RST to tap/guest, close socket
|
|
* - on zero read, send FIN to tap/guest, set TAP_FIN_SENT
|
|
* - on ACK from tap/guest:
|
|
* - set @ts_ack_from_tap
|
|
* - check if it's the second duplicated ACK
|
|
* - consume buffer by difference between new ack_seq and @seq_ack_from_tap
|
|
* - update @seq_ack_from_tap from ack_seq in header
|
|
* - on two duplicated ACKs, reset @seq_to_tap to @seq_ack_from_tap, and
|
|
* resend with steps listed above
|
|
*
|
|
* - from tap/guest to socket:
|
|
* - on packet from tap/guest:
|
|
* - set @ts_tap_act
|
|
* - check seq from header against @seq_from_tap, if data is missing, send
|
|
* two ACKs with number @seq_ack_to_tap, discard packet
|
|
* - otherwise queue data to socket, set @seq_from_tap to seq from header
|
|
* plus payload length
|
|
* - in ESTABLISHED state, send ACK to tap as soon as we queue to the
|
|
* socket. In other states, query socket for TCP_INFO, set
|
|
* @seq_ack_to_tap to (tcpi_bytes_acked + @seq_init_from_tap) % 2^32 and
|
|
* send ACK to tap/guest
|
|
*
|
|
*
|
|
* PASTA mode
|
|
* ==========
|
|
*
|
|
* For traffic directed to TCP ports configured for mapping to the tuntap device
|
|
* in the namespace, and for non-local traffic coming from the tuntap device,
|
|
* the implementation is identical as the PASST mode described in the previous
|
|
* section.
|
|
*
|
|
* For local traffic directed to TCP ports configured for direct mapping between
|
|
* namespaces, see the implementation in tcp_splice.c.
|
|
*/
|
|
|
|
#include <sched.h>
|
|
#include <fcntl.h>
|
|
#include <stdio.h>
|
|
#include <unistd.h>
|
|
#include <signal.h>
|
|
#include <stdlib.h>
|
|
#include <errno.h>
|
|
#include <limits.h>
|
|
#include <net/ethernet.h>
|
|
#include <net/if.h>
|
|
#include <netinet/in.h>
|
|
#include <netinet/ip.h>
|
|
#include <stdint.h>
|
|
#include <stdbool.h>
|
|
#include <stddef.h>
|
|
#include <string.h>
|
|
#include <sys/epoll.h>
|
|
#include <sys/socket.h>
|
|
#include <sys/timerfd.h>
|
|
#include <sys/types.h>
|
|
#include <sys/uio.h>
|
|
#include <time.h>
|
|
#include <arpa/inet.h>
|
|
|
|
#include <linux/tcp.h> /* For struct tcp_info */
|
|
|
|
#include "checksum.h"
|
|
#include "util.h"
|
|
#include "ip.h"
|
|
#include "passt.h"
|
|
#include "tap.h"
|
|
#include "siphash.h"
|
|
#include "pcap.h"
|
|
#include "tcp_splice.h"
|
|
#include "log.h"
|
|
#include "inany.h"
|
|
#include "flow.h"
|
|
|
|
#include "flow_table.h"
|
|
|
|
/* Sides of a flow as we use them in "tap" connections */
|
|
#define SOCKSIDE 0
|
|
#define TAPSIDE 1
|
|
|
|
#define TCP_FRAMES_MEM 128
|
|
#define TCP_FRAMES \
|
|
(c->mode == MODE_PASST ? TCP_FRAMES_MEM : 1)
|
|
|
|
#define TCP_HASH_TABLE_LOAD 70 /* % */
|
|
#define TCP_HASH_TABLE_SIZE (FLOW_MAX * 100 / TCP_HASH_TABLE_LOAD)
|
|
|
|
#define MAX_WS 8
|
|
#define MAX_WINDOW (1 << (16 + (MAX_WS)))
|
|
|
|
/* MSS rounding: see SET_MSS() */
|
|
#define MSS_DEFAULT 536
|
|
#define MSS (USHRT_MAX - sizeof(struct tcphdr))
|
|
|
|
#define WINDOW_DEFAULT 14600 /* RFC 6928 */
|
|
#ifdef HAS_SND_WND
|
|
# define KERNEL_REPORTS_SND_WND(c) (c->tcp.kernel_snd_wnd)
|
|
#else
|
|
# define KERNEL_REPORTS_SND_WND(c) (0 && (c))
|
|
#endif
|
|
|
|
#define ACK_INTERVAL 10 /* ms */
|
|
#define SYN_TIMEOUT 10 /* s */
|
|
#define ACK_TIMEOUT 2
|
|
#define FIN_TIMEOUT 60
|
|
#define ACT_TIMEOUT 7200
|
|
|
|
#define LOW_RTT_TABLE_SIZE 8
|
|
#define LOW_RTT_THRESHOLD 10 /* us */
|
|
|
|
/* We need to include <linux/tcp.h> for tcpi_bytes_acked, instead of
|
|
* <netinet/tcp.h>, but that doesn't include a definition for SOL_TCP
|
|
*/
|
|
#define SOL_TCP IPPROTO_TCP
|
|
|
|
#define SEQ_LE(a, b) ((b) - (a) < MAX_WINDOW)
|
|
#define SEQ_LT(a, b) ((b) - (a) - 1 < MAX_WINDOW)
|
|
#define SEQ_GE(a, b) ((a) - (b) < MAX_WINDOW)
|
|
#define SEQ_GT(a, b) ((a) - (b) - 1 < MAX_WINDOW)
|
|
|
|
#define FIN (1 << 0)
|
|
#define SYN (1 << 1)
|
|
#define RST (1 << 2)
|
|
#define ACK (1 << 4)
|
|
/* Flags for internal usage */
|
|
#define DUP_ACK (1 << 5)
|
|
#define ACK_IF_NEEDED 0 /* See tcp_send_flag() */
|
|
|
|
#define OPT_EOL 0
|
|
#define OPT_NOP 1
|
|
#define OPT_MSS 2
|
|
#define OPT_MSS_LEN 4
|
|
#define OPT_WS 3
|
|
#define OPT_WS_LEN 3
|
|
#define OPT_SACKP 4
|
|
#define OPT_SACK 5
|
|
#define OPT_TS 8
|
|
|
|
#define CONN_V4(conn) (!!inany_v4(&(conn)->faddr))
|
|
#define CONN_V6(conn) (!CONN_V4(conn))
|
|
#define CONN_IS_CLOSING(conn) \
|
|
((conn->events & ESTABLISHED) && \
|
|
(conn->events & (SOCK_FIN_RCVD | TAP_FIN_RCVD)))
|
|
#define CONN_HAS(conn, set) ((conn->events & (set)) == (set))
|
|
|
|
static const char *tcp_event_str[] __attribute((__unused__)) = {
|
|
"SOCK_ACCEPTED", "TAP_SYN_RCVD", "ESTABLISHED", "TAP_SYN_ACK_SENT",
|
|
|
|
"SOCK_FIN_RCVD", "SOCK_FIN_SENT", "TAP_FIN_RCVD", "TAP_FIN_SENT",
|
|
"TAP_FIN_ACKED",
|
|
};
|
|
|
|
static const char *tcp_state_str[] __attribute((__unused__)) = {
|
|
"SYN_RCVD", "SYN_SENT", "ESTABLISHED",
|
|
"SYN_RCVD", /* approximately maps to TAP_SYN_ACK_SENT */
|
|
|
|
/* Passive close: */
|
|
"CLOSE_WAIT", "CLOSE_WAIT", "LAST_ACK", "LAST_ACK", "LAST_ACK",
|
|
/* Active close (+5): */
|
|
"CLOSING", "FIN_WAIT_1", "FIN_WAIT_1", "FIN_WAIT_2", "TIME_WAIT",
|
|
};
|
|
|
|
static const char *tcp_flag_str[] __attribute((__unused__)) = {
|
|
"STALLED", "LOCAL", "ACTIVE_CLOSE", "ACK_TO_TAP_DUE",
|
|
"ACK_FROM_TAP_DUE",
|
|
};
|
|
|
|
/* Listening sockets, used for automatic port forwarding in pasta mode only */
|
|
static int tcp_sock_init_ext [NUM_PORTS][IP_VERSIONS];
|
|
static int tcp_sock_ns [NUM_PORTS][IP_VERSIONS];
|
|
|
|
/* Table of guest side forwarding addresses with very low RTT (assumed
|
|
* to be local to the host), LRU
|
|
*/
|
|
static union inany_addr low_rtt_dst[LOW_RTT_TABLE_SIZE];
|
|
|
|
/**
|
|
* tcp_buf_seq_update - Sequences to update with length of frames once sent
|
|
* @seq: Pointer to sequence number sent to tap-side, to be updated
|
|
* @len: TCP payload length
|
|
*/
|
|
struct tcp_buf_seq_update {
|
|
uint32_t *seq;
|
|
uint16_t len;
|
|
};
|
|
|
|
/* Static buffers */
|
|
/**
|
|
* tcp_l2_flags_t - TCP header and data to send option flags
|
|
* @th: TCP header
|
|
* @opts TCP option flags
|
|
*/
|
|
struct tcp_l2_flags_t {
|
|
struct tcphdr th;
|
|
char opts[OPT_MSS_LEN + OPT_WS_LEN + 1];
|
|
};
|
|
/**
|
|
* tcp_l2_payload_t - TCP header and data to send data
|
|
* 32 bytes aligned to be able to use AVX2 checksum
|
|
* @th: TCP header
|
|
* @data: TCP data
|
|
*/
|
|
struct tcp_l2_payload_t {
|
|
struct tcphdr th; /* 20 bytes */
|
|
uint8_t data[MSS]; /* 65516 bytes */
|
|
#ifdef __AVX2__
|
|
} __attribute__ ((packed, aligned(32)));
|
|
#else
|
|
} __attribute__ ((packed, aligned(__alignof__(unsigned int))));
|
|
#endif
|
|
|
|
/* Ethernet header for IPv4 frames */
|
|
static struct ethhdr tcp4_eth_src;
|
|
|
|
/* IPv4 headers */
|
|
static struct iphdr tcp4_l2_ip[TCP_FRAMES_MEM];
|
|
/* TCP headers and data for IPv4 frames */
|
|
static struct tcp_l2_payload_t tcp4_l2_payload[TCP_FRAMES_MEM];
|
|
|
|
static struct tcp_buf_seq_update tcp4_l2_buf_seq_update[TCP_FRAMES_MEM];
|
|
static unsigned int tcp4_l2_buf_used;
|
|
|
|
/* IPv4 headers for TCP option flags frames */
|
|
static struct iphdr tcp4_l2_flags_ip[TCP_FRAMES_MEM];
|
|
/* TCP headers and option flags for IPv4 frames */
|
|
static struct tcp_l2_flags_t tcp4_l2_flags[TCP_FRAMES_MEM];
|
|
|
|
static unsigned int tcp4_l2_flags_buf_used;
|
|
|
|
/* Ethernet header for IPv6 frames */
|
|
static struct ethhdr tcp6_eth_src;
|
|
|
|
/* IPv6 headers */
|
|
static struct ipv6hdr tcp6_l2_ip[TCP_FRAMES_MEM];
|
|
/* TCP headers and data for IPv6 frames */
|
|
static struct tcp_l2_payload_t tcp6_l2_payload[TCP_FRAMES_MEM];
|
|
|
|
static struct tcp_buf_seq_update tcp6_l2_buf_seq_update[TCP_FRAMES_MEM];
|
|
static unsigned int tcp6_l2_buf_used;
|
|
|
|
/* IPv6 headers for TCP option flags frames */
|
|
static struct ipv6hdr tcp6_l2_flags_ip[TCP_FRAMES_MEM];
|
|
/* TCP headers and option flags for IPv6 frames */
|
|
static struct tcp_l2_flags_t tcp6_l2_flags[TCP_FRAMES_MEM];
|
|
|
|
static unsigned int tcp6_l2_flags_buf_used;
|
|
|
|
/* recvmsg()/sendmsg() data for tap */
|
|
static char tcp_buf_discard [MAX_WINDOW];
|
|
static struct iovec iov_sock [TCP_FRAMES_MEM + 1];
|
|
|
|
static struct iovec tcp4_l2_iov [TCP_FRAMES_MEM][TCP_IOV_NUM];
|
|
static struct iovec tcp6_l2_iov [TCP_FRAMES_MEM][TCP_IOV_NUM];
|
|
static struct iovec tcp4_l2_flags_iov [TCP_FRAMES_MEM][TCP_IOV_NUM];
|
|
static struct iovec tcp6_l2_flags_iov [TCP_FRAMES_MEM][TCP_IOV_NUM];
|
|
|
|
/* sendmsg() to socket */
|
|
static struct iovec tcp_iov [UIO_MAXIOV];
|
|
|
|
#define CONN(idx) (&(FLOW(idx)->tcp))
|
|
|
|
/* Table for lookup from remote address, local port, remote port */
|
|
static flow_sidx_t tc_hash[TCP_HASH_TABLE_SIZE];
|
|
|
|
static_assert(ARRAY_SIZE(tc_hash) >= FLOW_MAX,
|
|
"Safe linear probing requires hash table larger than connection table");
|
|
|
|
/* Pools for pre-opened sockets (in init) */
|
|
int init_sock_pool4 [TCP_SOCK_POOL_SIZE];
|
|
int init_sock_pool6 [TCP_SOCK_POOL_SIZE];
|
|
|
|
/**
|
|
* tcp_conn_epoll_events() - epoll events mask for given connection state
|
|
* @events: Current connection events
|
|
* @conn_flags Connection flags
|
|
*
|
|
* Return: epoll events mask corresponding to implied connection state
|
|
*/
|
|
static uint32_t tcp_conn_epoll_events(uint8_t events, uint8_t conn_flags)
|
|
{
|
|
if (!events)
|
|
return 0;
|
|
|
|
if (events & ESTABLISHED) {
|
|
if (events & TAP_FIN_SENT)
|
|
return EPOLLET;
|
|
|
|
if (conn_flags & STALLED)
|
|
return EPOLLIN | EPOLLOUT | EPOLLRDHUP | EPOLLET;
|
|
|
|
return EPOLLIN | EPOLLRDHUP;
|
|
}
|
|
|
|
if (events == TAP_SYN_RCVD)
|
|
return EPOLLOUT | EPOLLET | EPOLLRDHUP;
|
|
|
|
return EPOLLRDHUP;
|
|
}
|
|
|
|
static void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn,
|
|
unsigned long flag);
|
|
#define conn_flag(c, conn, flag) \
|
|
do { \
|
|
flow_trace(conn, "flag at %s:%i", __func__, __LINE__); \
|
|
conn_flag_do(c, conn, flag); \
|
|
} while (0)
|
|
|
|
/**
|
|
* tcp_epoll_ctl() - Add/modify/delete epoll state from connection events
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
*
|
|
* Return: 0 on success, negative error code on failure (not on deletion)
|
|
*/
|
|
static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
|
|
{
|
|
int m = conn->in_epoll ? EPOLL_CTL_MOD : EPOLL_CTL_ADD;
|
|
union epoll_ref ref = { .type = EPOLL_TYPE_TCP, .fd = conn->sock,
|
|
.flowside = FLOW_SIDX(conn, SOCKSIDE) };
|
|
struct epoll_event ev = { .data.u64 = ref.u64 };
|
|
|
|
if (conn->events == CLOSED) {
|
|
if (conn->in_epoll)
|
|
epoll_ctl(c->epollfd, EPOLL_CTL_DEL, conn->sock, &ev);
|
|
if (conn->timer != -1)
|
|
epoll_ctl(c->epollfd, EPOLL_CTL_DEL, conn->timer, &ev);
|
|
return 0;
|
|
}
|
|
|
|
ev.events = tcp_conn_epoll_events(conn->events, conn->flags);
|
|
|
|
if (epoll_ctl(c->epollfd, m, conn->sock, &ev))
|
|
return -errno;
|
|
|
|
conn->in_epoll = true;
|
|
|
|
if (conn->timer != -1) {
|
|
union epoll_ref ref_t = { .type = EPOLL_TYPE_TCP_TIMER,
|
|
.fd = conn->sock,
|
|
.flow = FLOW_IDX(conn) };
|
|
struct epoll_event ev_t = { .data.u64 = ref_t.u64,
|
|
.events = EPOLLIN | EPOLLET };
|
|
|
|
if (epoll_ctl(c->epollfd, EPOLL_CTL_MOD, conn->timer, &ev_t))
|
|
return -errno;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_timer_ctl() - Set timerfd based on flags/events, create timerfd if needed
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
*
|
|
* #syscalls timerfd_create timerfd_settime
|
|
*/
|
|
static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
|
|
{
|
|
struct itimerspec it = { { 0 }, { 0 } };
|
|
|
|
if (conn->events == CLOSED)
|
|
return;
|
|
|
|
if (conn->timer == -1) {
|
|
union epoll_ref ref = { .type = EPOLL_TYPE_TCP_TIMER,
|
|
.fd = conn->sock,
|
|
.flow = FLOW_IDX(conn) };
|
|
struct epoll_event ev = { .data.u64 = ref.u64,
|
|
.events = EPOLLIN | EPOLLET };
|
|
int fd;
|
|
|
|
fd = timerfd_create(CLOCK_MONOTONIC, 0);
|
|
if (fd == -1 || fd > FD_REF_MAX) {
|
|
flow_dbg(conn, "failed to get timer: %s",
|
|
strerror(errno));
|
|
if (fd > -1)
|
|
close(fd);
|
|
conn->timer = -1;
|
|
return;
|
|
}
|
|
conn->timer = fd;
|
|
|
|
if (epoll_ctl(c->epollfd, EPOLL_CTL_ADD, conn->timer, &ev)) {
|
|
flow_dbg(conn, "failed to add timer: %s",
|
|
strerror(errno));
|
|
close(conn->timer);
|
|
conn->timer = -1;
|
|
return;
|
|
}
|
|
}
|
|
|
|
if (conn->flags & ACK_TO_TAP_DUE) {
|
|
it.it_value.tv_nsec = (long)ACK_INTERVAL * 1000 * 1000;
|
|
} else if (conn->flags & ACK_FROM_TAP_DUE) {
|
|
if (!(conn->events & ESTABLISHED))
|
|
it.it_value.tv_sec = SYN_TIMEOUT;
|
|
else
|
|
it.it_value.tv_sec = ACK_TIMEOUT;
|
|
} else if (CONN_HAS(conn, SOCK_FIN_SENT | TAP_FIN_ACKED)) {
|
|
it.it_value.tv_sec = FIN_TIMEOUT;
|
|
} else {
|
|
it.it_value.tv_sec = ACT_TIMEOUT;
|
|
}
|
|
|
|
flow_dbg(conn, "timer expires in %llu.%03llus",
|
|
(unsigned long long)it.it_value.tv_sec,
|
|
(unsigned long long)it.it_value.tv_nsec / 1000 / 1000);
|
|
|
|
timerfd_settime(conn->timer, 0, &it, NULL);
|
|
}
|
|
|
|
/**
|
|
* conn_flag_do() - Set/unset given flag, log, update epoll on STALLED flag
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
* @flag: Flag to set, or ~flag to unset
|
|
*/
|
|
static void conn_flag_do(const struct ctx *c, struct tcp_tap_conn *conn,
|
|
unsigned long flag)
|
|
{
|
|
if (flag & (flag - 1)) {
|
|
int flag_index = fls(~flag);
|
|
|
|
if (!(conn->flags & ~flag))
|
|
return;
|
|
|
|
conn->flags &= flag;
|
|
if (flag_index >= 0)
|
|
flow_dbg(conn, "%s dropped", tcp_flag_str[flag_index]);
|
|
} else {
|
|
int flag_index = fls(flag);
|
|
|
|
if (conn->flags & flag) {
|
|
/* Special case: setting ACK_FROM_TAP_DUE on a
|
|
* connection where it's already set is used to
|
|
* re-schedule the existing timer.
|
|
* TODO: define clearer semantics for timer-related
|
|
* flags and factor this into the logic below.
|
|
*/
|
|
if (flag == ACK_FROM_TAP_DUE)
|
|
tcp_timer_ctl(c, conn);
|
|
|
|
return;
|
|
}
|
|
|
|
conn->flags |= flag;
|
|
if (flag_index >= 0)
|
|
flow_dbg(conn, "%s", tcp_flag_str[flag_index]);
|
|
}
|
|
|
|
if (flag == STALLED || flag == ~STALLED)
|
|
tcp_epoll_ctl(c, conn);
|
|
|
|
if (flag == ACK_FROM_TAP_DUE || flag == ACK_TO_TAP_DUE ||
|
|
(flag == ~ACK_FROM_TAP_DUE && (conn->flags & ACK_TO_TAP_DUE)) ||
|
|
(flag == ~ACK_TO_TAP_DUE && (conn->flags & ACK_FROM_TAP_DUE)))
|
|
tcp_timer_ctl(c, conn);
|
|
}
|
|
|
|
static void tcp_hash_remove(const struct ctx *c,
|
|
const struct tcp_tap_conn *conn);
|
|
|
|
/**
|
|
* conn_event_do() - Set and log connection events, update epoll state
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
* @event: Connection event
|
|
*/
|
|
static void conn_event_do(const struct ctx *c, struct tcp_tap_conn *conn,
|
|
unsigned long event)
|
|
{
|
|
int prev, new, num = fls(event);
|
|
|
|
if (conn->events & event)
|
|
return;
|
|
|
|
prev = fls(conn->events);
|
|
if (conn->flags & ACTIVE_CLOSE)
|
|
prev += 5;
|
|
|
|
if ((conn->events & ESTABLISHED) && (conn->events != ESTABLISHED))
|
|
prev++; /* i.e. SOCK_FIN_RCVD, not TAP_SYN_ACK_SENT */
|
|
|
|
if (event == CLOSED || (event & CONN_STATE_BITS))
|
|
conn->events = event;
|
|
else
|
|
conn->events |= event;
|
|
|
|
new = fls(conn->events);
|
|
|
|
if ((conn->events & ESTABLISHED) && (conn->events != ESTABLISHED)) {
|
|
num++;
|
|
new++;
|
|
}
|
|
if (conn->flags & ACTIVE_CLOSE)
|
|
new += 5;
|
|
|
|
if (prev != new)
|
|
flow_dbg(conn, "%s: %s -> %s",
|
|
num == -1 ? "CLOSED" : tcp_event_str[num],
|
|
prev == -1 ? "CLOSED" : tcp_state_str[prev],
|
|
(new == -1 || num == -1) ? "CLOSED" : tcp_state_str[new]);
|
|
else
|
|
flow_dbg(conn, "%s",
|
|
num == -1 ? "CLOSED" : tcp_event_str[num]);
|
|
|
|
if (event == CLOSED)
|
|
tcp_hash_remove(c, conn);
|
|
else if ((event == TAP_FIN_RCVD) && !(conn->events & SOCK_FIN_RCVD))
|
|
conn_flag(c, conn, ACTIVE_CLOSE);
|
|
else
|
|
tcp_epoll_ctl(c, conn);
|
|
|
|
if (CONN_HAS(conn, SOCK_FIN_SENT | TAP_FIN_ACKED))
|
|
tcp_timer_ctl(c, conn);
|
|
}
|
|
|
|
#define conn_event(c, conn, event) \
|
|
do { \
|
|
flow_trace(conn, "event at %s:%i", __func__, __LINE__); \
|
|
conn_event_do(c, conn, event); \
|
|
} while (0)
|
|
|
|
/**
|
|
* tcp_rtt_dst_low() - Check if low RTT was seen for connection endpoint
|
|
* @conn: Connection pointer
|
|
*
|
|
* Return: 1 if destination is in low RTT table, 0 otherwise
|
|
*/
|
|
static int tcp_rtt_dst_low(const struct tcp_tap_conn *conn)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < LOW_RTT_TABLE_SIZE; i++)
|
|
if (inany_equals(&conn->faddr, low_rtt_dst + i))
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_rtt_dst_check() - Check tcpi_min_rtt, insert endpoint in table if low
|
|
* @conn: Connection pointer
|
|
* @tinfo: Pointer to struct tcp_info for socket
|
|
*/
|
|
static void tcp_rtt_dst_check(const struct tcp_tap_conn *conn,
|
|
const struct tcp_info *tinfo)
|
|
{
|
|
#ifdef HAS_MIN_RTT
|
|
int i, hole = -1;
|
|
|
|
if (!tinfo->tcpi_min_rtt ||
|
|
(int)tinfo->tcpi_min_rtt > LOW_RTT_THRESHOLD)
|
|
return;
|
|
|
|
for (i = 0; i < LOW_RTT_TABLE_SIZE; i++) {
|
|
if (inany_equals(&conn->faddr, low_rtt_dst + i))
|
|
return;
|
|
if (hole == -1 && IN6_IS_ADDR_UNSPECIFIED(low_rtt_dst + i))
|
|
hole = i;
|
|
}
|
|
|
|
/* Keep gcc 12 happy: this won't actually happen because the table is
|
|
* guaranteed to have a hole, see the second memcpy() below.
|
|
*/
|
|
if (hole == -1)
|
|
return;
|
|
|
|
low_rtt_dst[hole++] = conn->faddr;
|
|
if (hole == LOW_RTT_TABLE_SIZE)
|
|
hole = 0;
|
|
inany_from_af(low_rtt_dst + hole, AF_INET6, &in6addr_any);
|
|
#else
|
|
(void)conn;
|
|
(void)tinfo;
|
|
#endif /* HAS_MIN_RTT */
|
|
}
|
|
|
|
/**
|
|
* tcp_get_sndbuf() - Get, scale SO_SNDBUF between thresholds (1 to 0.5 usage)
|
|
* @conn: Connection pointer
|
|
*/
|
|
static void tcp_get_sndbuf(struct tcp_tap_conn *conn)
|
|
{
|
|
int s = conn->sock, sndbuf;
|
|
socklen_t sl;
|
|
uint64_t v;
|
|
|
|
sl = sizeof(sndbuf);
|
|
if (getsockopt(s, SOL_SOCKET, SO_SNDBUF, &sndbuf, &sl)) {
|
|
SNDBUF_SET(conn, WINDOW_DEFAULT);
|
|
return;
|
|
}
|
|
|
|
v = sndbuf;
|
|
if (v >= SNDBUF_BIG)
|
|
v /= 2;
|
|
else if (v > SNDBUF_SMALL)
|
|
v -= v * (v - SNDBUF_SMALL) / (SNDBUF_BIG - SNDBUF_SMALL) / 2;
|
|
|
|
SNDBUF_SET(conn, MIN(INT_MAX, v));
|
|
}
|
|
|
|
/**
|
|
* tcp_sock_set_bufsize() - Set SO_RCVBUF and SO_SNDBUF to maximum values
|
|
* @s: Socket, can be -1 to avoid check in the caller
|
|
*/
|
|
static void tcp_sock_set_bufsize(const struct ctx *c, int s)
|
|
{
|
|
int v = INT_MAX / 2; /* Kernel clamps and rounds, no need to check */
|
|
|
|
if (s == -1)
|
|
return;
|
|
|
|
if (!c->low_rmem && setsockopt(s, SOL_SOCKET, SO_RCVBUF, &v, sizeof(v)))
|
|
trace("TCP: failed to set SO_RCVBUF to %i", v);
|
|
|
|
if (!c->low_wmem && setsockopt(s, SOL_SOCKET, SO_SNDBUF, &v, sizeof(v)))
|
|
trace("TCP: failed to set SO_SNDBUF to %i", v);
|
|
}
|
|
|
|
/**
|
|
* tcp_update_check_tcp4() - Update TCP checksum from stored one
|
|
* @iph: IPv4 header
|
|
* @th: TCP header followed by TCP payload
|
|
*/
|
|
static void tcp_update_check_tcp4(const struct iphdr *iph, struct tcphdr *th)
|
|
{
|
|
uint16_t tlen = ntohs(iph->tot_len) - sizeof(struct iphdr);
|
|
struct in_addr saddr = { .s_addr = iph->saddr };
|
|
struct in_addr daddr = { .s_addr = iph->daddr };
|
|
uint32_t sum = proto_ipv4_header_psum(tlen, IPPROTO_TCP, saddr, daddr);
|
|
|
|
th->check = 0;
|
|
th->check = csum(th, tlen, sum);
|
|
}
|
|
|
|
/**
|
|
* tcp_update_check_tcp6() - Calculate TCP checksum for IPv6
|
|
* @ip6h: IPv6 header
|
|
* @th: TCP header followed by TCP payload
|
|
*/
|
|
static void tcp_update_check_tcp6(struct ipv6hdr *ip6h, struct tcphdr *th)
|
|
{
|
|
uint16_t payload_len = ntohs(ip6h->payload_len);
|
|
uint32_t sum = proto_ipv6_header_psum(payload_len, IPPROTO_TCP,
|
|
&ip6h->saddr, &ip6h->daddr);
|
|
|
|
th->check = 0;
|
|
th->check = csum(th, payload_len, sum);
|
|
}
|
|
|
|
/**
|
|
* tcp_update_l2_buf() - Update L2 buffers with Ethernet and IPv4 addresses
|
|
* @eth_d: Ethernet destination address, NULL if unchanged
|
|
* @eth_s: Ethernet source address, NULL if unchanged
|
|
*/
|
|
void tcp_update_l2_buf(const unsigned char *eth_d, const unsigned char *eth_s)
|
|
{
|
|
eth_update_mac(&tcp4_eth_src, eth_d, eth_s);
|
|
eth_update_mac(&tcp6_eth_src, eth_d, eth_s);
|
|
}
|
|
|
|
/**
|
|
* tcp_sock4_iov_init() - Initialise scatter-gather L2 buffers for IPv4 sockets
|
|
* @c: Execution context
|
|
*/
|
|
static void tcp_sock4_iov_init(const struct ctx *c)
|
|
{
|
|
struct iphdr iph = L2_BUF_IP4_INIT(IPPROTO_TCP);
|
|
int i;
|
|
|
|
(void)c;
|
|
|
|
tcp4_eth_src.h_proto = htons_constant(ETH_P_IP);
|
|
for (i = 0; i < TCP_FRAMES_MEM; i++) {
|
|
struct iovec *iov;
|
|
|
|
/* headers */
|
|
tcp4_l2_ip[i] = iph;
|
|
tcp4_l2_payload[i].th = (struct tcphdr){
|
|
.doff = sizeof(struct tcphdr) / 4,
|
|
.ack = 1
|
|
};
|
|
|
|
tcp4_l2_flags_ip[i] = iph;
|
|
tcp4_l2_flags[i].th = (struct tcphdr){
|
|
.doff = sizeof(struct tcphdr) / 4,
|
|
.ack = 1
|
|
};
|
|
|
|
/* iovecs */
|
|
iov = tcp4_l2_iov[i];
|
|
iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src;
|
|
iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr);
|
|
iov[TCP_IOV_IP].iov_base = &tcp4_l2_ip[i];
|
|
iov[TCP_IOV_IP].iov_len = sizeof(struct iphdr);
|
|
iov[TCP_IOV_PAYLOAD].iov_base = &tcp4_l2_payload[i];
|
|
|
|
iov = tcp4_l2_flags_iov[i];
|
|
iov[TCP_IOV_ETH].iov_base = &tcp4_eth_src;
|
|
iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr);
|
|
iov[TCP_IOV_IP].iov_base = &tcp4_l2_flags_ip[i];
|
|
iov[TCP_IOV_IP].iov_len = sizeof(struct iphdr);
|
|
iov[TCP_IOV_PAYLOAD].iov_base = &tcp4_l2_flags[i];
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tcp_sock6_iov_init() - Initialise scatter-gather L2 buffers for IPv6 sockets
|
|
* @c: Execution context
|
|
*/
|
|
static void tcp_sock6_iov_init(const struct ctx *c)
|
|
{
|
|
struct ipv6hdr ip6 = L2_BUF_IP6_INIT(IPPROTO_TCP);
|
|
int i;
|
|
|
|
(void)c;
|
|
|
|
tcp6_eth_src.h_proto = htons_constant(ETH_P_IPV6);
|
|
for (i = 0; i < TCP_FRAMES_MEM; i++) {
|
|
struct iovec *iov;
|
|
|
|
/* headers */
|
|
tcp6_l2_ip[i] = ip6;
|
|
tcp6_l2_payload[i].th = (struct tcphdr){
|
|
.doff = sizeof(struct tcphdr) / 4,
|
|
.ack = 1
|
|
};
|
|
|
|
tcp6_l2_flags_ip[i] = ip6;
|
|
tcp6_l2_flags[i].th = (struct tcphdr){
|
|
.doff = sizeof(struct tcphdr) / 4,
|
|
.ack = 1
|
|
};
|
|
|
|
/* iovecs */
|
|
iov = tcp6_l2_iov[i];
|
|
iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src;
|
|
iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr);
|
|
iov[TCP_IOV_IP].iov_base = &tcp6_l2_ip[i];
|
|
iov[TCP_IOV_IP].iov_len = sizeof(struct ipv6hdr);
|
|
iov[TCP_IOV_PAYLOAD].iov_base = &tcp6_l2_payload[i];
|
|
|
|
iov = tcp6_l2_flags_iov[i];
|
|
iov[TCP_IOV_ETH].iov_base = &tcp6_eth_src;
|
|
iov[TCP_IOV_ETH].iov_len = sizeof(struct ethhdr);
|
|
iov[TCP_IOV_IP].iov_base = &tcp6_l2_flags_ip[i];
|
|
iov[TCP_IOV_IP].iov_len = sizeof(struct ipv6hdr);
|
|
iov[TCP_IOV_PAYLOAD].iov_base = &tcp6_l2_flags[i];
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tcp_opt_get() - Get option, and value if any, from TCP header
|
|
* @opts: Pointer to start of TCP options in header
|
|
* @len: Length of buffer, excluding TCP header -- NOT checked here!
|
|
* @type_find: Option type to look for
|
|
* @optlen_set: Optional, filled with option length if passed
|
|
* @value_set: Optional, set to start of option value if passed
|
|
*
|
|
* Return: option value, meaningful for up to 4 bytes, -1 if not found
|
|
*/
|
|
static int tcp_opt_get(const char *opts, size_t len, uint8_t type_find,
|
|
uint8_t *optlen_set, const char **value_set)
|
|
{
|
|
uint8_t type, optlen;
|
|
|
|
if (!opts || !len)
|
|
return -1;
|
|
|
|
for (; len >= 2; opts += optlen, len -= optlen) {
|
|
switch (*opts) {
|
|
case OPT_EOL:
|
|
return -1;
|
|
case OPT_NOP:
|
|
optlen = 1;
|
|
break;
|
|
default:
|
|
type = *(opts++);
|
|
|
|
if (*(uint8_t *)opts < 2 || *(uint8_t *)opts > len)
|
|
return -1;
|
|
|
|
optlen = *(opts++) - 2;
|
|
len -= 2;
|
|
|
|
if (type != type_find)
|
|
break;
|
|
|
|
if (optlen_set)
|
|
*optlen_set = optlen;
|
|
if (value_set)
|
|
*value_set = opts;
|
|
|
|
switch (optlen) {
|
|
case 0:
|
|
return 0;
|
|
case 1:
|
|
return *opts;
|
|
case 2:
|
|
return ntohs(*(uint16_t *)opts);
|
|
default:
|
|
return ntohl(*(uint32_t *)opts);
|
|
}
|
|
}
|
|
}
|
|
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* tcp_hash_match() - Check if a connection entry matches address and ports
|
|
* @conn: Connection entry to match against
|
|
* @faddr: Guest side forwarding address
|
|
* @eport: Guest side endpoint port
|
|
* @fport: Guest side forwarding port
|
|
*
|
|
* Return: 1 on match, 0 otherwise
|
|
*/
|
|
static int tcp_hash_match(const struct tcp_tap_conn *conn,
|
|
const union inany_addr *faddr,
|
|
in_port_t eport, in_port_t fport)
|
|
{
|
|
if (inany_equals(&conn->faddr, faddr) &&
|
|
conn->eport == eport && conn->fport == fport)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_hash() - Calculate hash value for connection given address and ports
|
|
* @c: Execution context
|
|
* @faddr: Guest side forwarding address
|
|
* @eport: Guest side endpoint port
|
|
* @fport: Guest side forwarding port
|
|
*
|
|
* Return: hash value, needs to be adjusted for table size
|
|
*/
|
|
static uint64_t tcp_hash(const struct ctx *c, const union inany_addr *faddr,
|
|
in_port_t eport, in_port_t fport)
|
|
{
|
|
struct siphash_state state = SIPHASH_INIT(c->hash_secret);
|
|
|
|
inany_siphash_feed(&state, faddr);
|
|
return siphash_final(&state, 20, (uint64_t)eport << 16 | fport);
|
|
}
|
|
|
|
/**
|
|
* tcp_conn_hash() - Calculate hash bucket of an existing connection
|
|
* @c: Execution context
|
|
* @conn: Connection
|
|
*
|
|
* Return: hash value, needs to be adjusted for table size
|
|
*/
|
|
static uint64_t tcp_conn_hash(const struct ctx *c,
|
|
const struct tcp_tap_conn *conn)
|
|
{
|
|
return tcp_hash(c, &conn->faddr, conn->eport, conn->fport);
|
|
}
|
|
|
|
/**
|
|
* tcp_hash_probe() - Find hash bucket for a connection
|
|
* @c: Execution context
|
|
* @conn: Connection to find bucket for
|
|
*
|
|
* Return: If @conn is in the table, its current bucket, otherwise a suitable
|
|
* free bucket for it.
|
|
*/
|
|
static inline unsigned tcp_hash_probe(const struct ctx *c,
|
|
const struct tcp_tap_conn *conn)
|
|
{
|
|
flow_sidx_t sidx = FLOW_SIDX(conn, TAPSIDE);
|
|
unsigned b = tcp_conn_hash(c, conn) % TCP_HASH_TABLE_SIZE;
|
|
|
|
/* Linear probing */
|
|
while (!flow_sidx_eq(tc_hash[b], FLOW_SIDX_NONE) &&
|
|
!flow_sidx_eq(tc_hash[b], sidx))
|
|
b = mod_sub(b, 1, TCP_HASH_TABLE_SIZE);
|
|
|
|
return b;
|
|
}
|
|
|
|
/**
|
|
* tcp_hash_insert() - Insert connection into hash table, chain link
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
*/
|
|
static void tcp_hash_insert(const struct ctx *c, struct tcp_tap_conn *conn)
|
|
{
|
|
unsigned b = tcp_hash_probe(c, conn);
|
|
|
|
tc_hash[b] = FLOW_SIDX(conn, TAPSIDE);
|
|
flow_dbg(conn, "hash table insert: sock %i, bucket: %u", conn->sock, b);
|
|
}
|
|
|
|
/**
|
|
* tcp_hash_remove() - Drop connection from hash table, chain unlink
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
*/
|
|
static void tcp_hash_remove(const struct ctx *c,
|
|
const struct tcp_tap_conn *conn)
|
|
{
|
|
unsigned b = tcp_hash_probe(c, conn), s;
|
|
union flow *flow = flow_at_sidx(tc_hash[b]);
|
|
|
|
if (!flow)
|
|
return; /* Redundant remove */
|
|
|
|
flow_dbg(conn, "hash table remove: sock %i, bucket: %u", conn->sock, b);
|
|
|
|
/* Scan the remainder of the cluster */
|
|
for (s = mod_sub(b, 1, TCP_HASH_TABLE_SIZE);
|
|
(flow = flow_at_sidx(tc_hash[s]));
|
|
s = mod_sub(s, 1, TCP_HASH_TABLE_SIZE)) {
|
|
unsigned h = tcp_conn_hash(c, &flow->tcp) % TCP_HASH_TABLE_SIZE;
|
|
|
|
if (!mod_between(h, s, b, TCP_HASH_TABLE_SIZE)) {
|
|
/* tc_hash[s] can live in tc_hash[b]'s slot */
|
|
debug("hash table remove: shuffle %u -> %u", s, b);
|
|
tc_hash[b] = tc_hash[s];
|
|
b = s;
|
|
}
|
|
}
|
|
|
|
tc_hash[b] = FLOW_SIDX_NONE;
|
|
}
|
|
|
|
/**
|
|
* tcp_hash_lookup() - Look up connection given remote address and ports
|
|
* @c: Execution context
|
|
* @af: Address family, AF_INET or AF_INET6
|
|
* @faddr: Guest side forwarding address (guest remote address)
|
|
* @eport: Guest side endpoint port (guest local port)
|
|
* @fport: Guest side forwarding port (guest remote port)
|
|
*
|
|
* Return: connection pointer, if found, -ENOENT otherwise
|
|
*/
|
|
static struct tcp_tap_conn *tcp_hash_lookup(const struct ctx *c,
|
|
sa_family_t af, const void *faddr,
|
|
in_port_t eport, in_port_t fport)
|
|
{
|
|
union inany_addr aany;
|
|
union flow *flow;
|
|
unsigned b;
|
|
|
|
inany_from_af(&aany, af, faddr);
|
|
|
|
b = tcp_hash(c, &aany, eport, fport) % TCP_HASH_TABLE_SIZE;
|
|
while ((flow = flow_at_sidx(tc_hash[b])) &&
|
|
!tcp_hash_match(&flow->tcp, &aany, eport, fport))
|
|
b = mod_sub(b, 1, TCP_HASH_TABLE_SIZE);
|
|
|
|
return &flow->tcp;
|
|
}
|
|
|
|
/**
|
|
* tcp_flow_defer() - Deferred per-flow handling (clean up closed connections)
|
|
* @flow: Flow table entry for this connection
|
|
*
|
|
* Return: true if the flow is ready to free, false otherwise
|
|
*/
|
|
bool tcp_flow_defer(union flow *flow)
|
|
{
|
|
const struct tcp_tap_conn *conn = &flow->tcp;
|
|
|
|
if (flow->tcp.events != CLOSED)
|
|
return false;
|
|
|
|
close(conn->sock);
|
|
if (conn->timer != -1)
|
|
close(conn->timer);
|
|
|
|
return true;
|
|
}
|
|
|
|
static void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn);
|
|
#define tcp_rst(c, conn) \
|
|
do { \
|
|
flow_dbg((conn), "TCP reset at %s:%i", __func__, __LINE__); \
|
|
tcp_rst_do(c, conn); \
|
|
} while (0)
|
|
|
|
/**
|
|
* tcp_l2_flags_buf_flush() - Send out buffers for segments with no data (flags)
|
|
* @c: Execution context
|
|
*/
|
|
static void tcp_l2_flags_buf_flush(const struct ctx *c)
|
|
{
|
|
tap_send_iov(c, tcp6_l2_flags_iov, tcp6_l2_flags_buf_used);
|
|
tcp6_l2_flags_buf_used = 0;
|
|
|
|
tap_send_iov(c, tcp4_l2_flags_iov, tcp4_l2_flags_buf_used);
|
|
tcp4_l2_flags_buf_used = 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_l2_data_buf_flush() - Send out buffers for segments with data
|
|
* @c: Execution context
|
|
*/
|
|
static void tcp_l2_data_buf_flush(const struct ctx *c)
|
|
{
|
|
unsigned i;
|
|
size_t m;
|
|
|
|
m = tap_send_iov(c, tcp6_l2_iov, tcp6_l2_buf_used);
|
|
for (i = 0; i < m; i++)
|
|
*tcp6_l2_buf_seq_update[i].seq += tcp6_l2_buf_seq_update[i].len;
|
|
tcp6_l2_buf_used = 0;
|
|
|
|
m = tap_send_iov(c, tcp4_l2_iov, tcp4_l2_buf_used);
|
|
for (i = 0; i < m; i++)
|
|
*tcp4_l2_buf_seq_update[i].seq += tcp4_l2_buf_seq_update[i].len;
|
|
tcp4_l2_buf_used = 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_defer_handler() - Handler for TCP deferred tasks
|
|
* @c: Execution context
|
|
*/
|
|
/* cppcheck-suppress [constParameterPointer, unmatchedSuppression] */
|
|
void tcp_defer_handler(struct ctx *c)
|
|
{
|
|
tcp_l2_flags_buf_flush(c);
|
|
tcp_l2_data_buf_flush(c);
|
|
}
|
|
|
|
/**
|
|
* tcp_fill_header() - Fill the TCP header fields for a given TCP segment.
|
|
*
|
|
* @th: Pointer to the TCP header structure
|
|
* @conn: Pointer to the TCP connection structure
|
|
* @seq: Sequence number
|
|
*/
|
|
static void tcp_fill_header(struct tcphdr *th,
|
|
const struct tcp_tap_conn *conn, uint32_t seq)
|
|
{
|
|
th->source = htons(conn->fport);
|
|
th->dest = htons(conn->eport);
|
|
th->seq = htonl(seq);
|
|
th->ack_seq = htonl(conn->seq_ack_to_tap);
|
|
if (conn->events & ESTABLISHED) {
|
|
th->window = htons(conn->wnd_to_tap);
|
|
} else {
|
|
unsigned wnd = conn->wnd_to_tap << conn->ws_to_tap;
|
|
|
|
th->window = htons(MIN(wnd, USHRT_MAX));
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tcp_fill_headers4() - Fill 802.3, IPv4, TCP headers in pre-cooked buffers
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
* @iph: Pointer to IPv4 header
|
|
* @th: Pointer to TCP header
|
|
* @plen: Payload length (including TCP header options)
|
|
* @check: Checksum, if already known
|
|
* @seq: Sequence number for this segment
|
|
*
|
|
* Return: The total length of the IPv4 packet, host order
|
|
*/
|
|
static size_t tcp_fill_headers4(const struct ctx *c,
|
|
const struct tcp_tap_conn *conn,
|
|
struct iphdr *iph, struct tcphdr *th,
|
|
size_t plen, const uint16_t *check,
|
|
uint32_t seq)
|
|
{
|
|
size_t ip_len = plen + sizeof(struct iphdr) + sizeof(struct tcphdr);
|
|
const struct in_addr *a4 = inany_v4(&conn->faddr);
|
|
|
|
ASSERT(a4);
|
|
|
|
iph->tot_len = htons(ip_len);
|
|
iph->saddr = a4->s_addr;
|
|
iph->daddr = c->ip4.addr_seen.s_addr;
|
|
|
|
iph->check = check ? *check :
|
|
csum_ip4_header(iph->tot_len, IPPROTO_TCP,
|
|
*a4, c->ip4.addr_seen);
|
|
|
|
tcp_fill_header(th, conn, seq);
|
|
|
|
tcp_update_check_tcp4(iph, th);
|
|
|
|
return ip_len;
|
|
}
|
|
|
|
/**
|
|
* tcp_fill_headers6() - Fill 802.3, IPv6, TCP headers in pre-cooked buffers
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
* @ip6h: Pointer to IPv6 header
|
|
* @th: Pointer to TCP header
|
|
* @plen: Payload length (including TCP header options)
|
|
* @check: Checksum, if already known
|
|
* @seq: Sequence number for this segment
|
|
*
|
|
* Return: The total length of the IPv6 packet, host order
|
|
*/
|
|
static size_t tcp_fill_headers6(const struct ctx *c,
|
|
const struct tcp_tap_conn *conn,
|
|
struct ipv6hdr *ip6h, struct tcphdr *th,
|
|
size_t plen, uint32_t seq)
|
|
{
|
|
size_t ip_len = plen + sizeof(struct ipv6hdr) + sizeof(struct tcphdr);
|
|
|
|
ip6h->payload_len = htons(plen + sizeof(struct tcphdr));
|
|
ip6h->saddr = conn->faddr.a6;
|
|
if (IN6_IS_ADDR_LINKLOCAL(&ip6h->saddr))
|
|
ip6h->daddr = c->ip6.addr_ll_seen;
|
|
else
|
|
ip6h->daddr = c->ip6.addr_seen;
|
|
|
|
ip6h->hop_limit = 255;
|
|
ip6h->version = 6;
|
|
ip6h->nexthdr = IPPROTO_TCP;
|
|
|
|
ip6h->flow_lbl[0] = (conn->sock >> 16) & 0xf;
|
|
ip6h->flow_lbl[1] = (conn->sock >> 8) & 0xff;
|
|
ip6h->flow_lbl[2] = (conn->sock >> 0) & 0xff;
|
|
|
|
tcp_fill_header(th, conn, seq);
|
|
|
|
tcp_update_check_tcp6(ip6h, th);
|
|
|
|
return ip_len;
|
|
}
|
|
|
|
/**
|
|
* tcp_update_seqack_wnd() - Update ACK sequence and window to guest/tap
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
* @force_seq: Force ACK sequence to latest segment, instead of checking socket
|
|
* @tinfo: tcp_info from kernel, can be NULL if not pre-fetched
|
|
*
|
|
* Return: 1 if sequence or window were updated, 0 otherwise
|
|
*/
|
|
static int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn,
|
|
int force_seq, struct tcp_info *tinfo)
|
|
{
|
|
uint32_t prev_wnd_to_tap = conn->wnd_to_tap << conn->ws_to_tap;
|
|
uint32_t prev_ack_to_tap = conn->seq_ack_to_tap;
|
|
/* cppcheck-suppress [ctunullpointer, unmatchedSuppression] */
|
|
socklen_t sl = sizeof(*tinfo);
|
|
struct tcp_info tinfo_new;
|
|
uint32_t new_wnd_to_tap = prev_wnd_to_tap;
|
|
int s = conn->sock;
|
|
|
|
#ifndef HAS_BYTES_ACKED
|
|
(void)force_seq;
|
|
|
|
conn->seq_ack_to_tap = conn->seq_from_tap;
|
|
if (SEQ_LT(conn->seq_ack_to_tap, prev_ack_to_tap))
|
|
conn->seq_ack_to_tap = prev_ack_to_tap;
|
|
#else
|
|
if ((unsigned)SNDBUF_GET(conn) < SNDBUF_SMALL || tcp_rtt_dst_low(conn)
|
|
|| CONN_IS_CLOSING(conn) || (conn->flags & LOCAL) || force_seq) {
|
|
conn->seq_ack_to_tap = conn->seq_from_tap;
|
|
} else if (conn->seq_ack_to_tap != conn->seq_from_tap) {
|
|
if (!tinfo) {
|
|
tinfo = &tinfo_new;
|
|
if (getsockopt(s, SOL_TCP, TCP_INFO, tinfo, &sl))
|
|
return 0;
|
|
}
|
|
|
|
conn->seq_ack_to_tap = tinfo->tcpi_bytes_acked +
|
|
conn->seq_init_from_tap;
|
|
|
|
if (SEQ_LT(conn->seq_ack_to_tap, prev_ack_to_tap))
|
|
conn->seq_ack_to_tap = prev_ack_to_tap;
|
|
}
|
|
#endif /* !HAS_BYTES_ACKED */
|
|
|
|
if (!KERNEL_REPORTS_SND_WND(c)) {
|
|
tcp_get_sndbuf(conn);
|
|
new_wnd_to_tap = MIN(SNDBUF_GET(conn), MAX_WINDOW);
|
|
conn->wnd_to_tap = MIN(new_wnd_to_tap >> conn->ws_to_tap,
|
|
USHRT_MAX);
|
|
goto out;
|
|
}
|
|
|
|
if (!tinfo) {
|
|
if (prev_wnd_to_tap > WINDOW_DEFAULT) {
|
|
goto out;
|
|
}
|
|
tinfo = &tinfo_new;
|
|
if (getsockopt(s, SOL_TCP, TCP_INFO, tinfo, &sl)) {
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
#ifdef HAS_SND_WND
|
|
if ((conn->flags & LOCAL) || tcp_rtt_dst_low(conn)) {
|
|
new_wnd_to_tap = tinfo->tcpi_snd_wnd;
|
|
} else {
|
|
tcp_get_sndbuf(conn);
|
|
new_wnd_to_tap = MIN((int)tinfo->tcpi_snd_wnd,
|
|
SNDBUF_GET(conn));
|
|
}
|
|
#endif
|
|
|
|
new_wnd_to_tap = MIN(new_wnd_to_tap, MAX_WINDOW);
|
|
if (!(conn->events & ESTABLISHED))
|
|
new_wnd_to_tap = MAX(new_wnd_to_tap, WINDOW_DEFAULT);
|
|
|
|
conn->wnd_to_tap = MIN(new_wnd_to_tap >> conn->ws_to_tap, USHRT_MAX);
|
|
|
|
/* Certain cppcheck versions, e.g. 2.12.0 have a bug where they think
|
|
* the MIN() above restricts conn->wnd_to_tap to be zero. That's
|
|
* clearly incorrect, but until the bug is fixed, work around it.
|
|
* https://bugzilla.redhat.com/show_bug.cgi?id=2240705
|
|
* https://sourceforge.net/p/cppcheck/discussion/general/thread/f5b1a00646/
|
|
*/
|
|
/* cppcheck-suppress [knownConditionTrueFalse, unmatchedSuppression] */
|
|
if (!conn->wnd_to_tap)
|
|
conn_flag(c, conn, ACK_TO_TAP_DUE);
|
|
|
|
out:
|
|
return new_wnd_to_tap != prev_wnd_to_tap ||
|
|
conn->seq_ack_to_tap != prev_ack_to_tap;
|
|
}
|
|
|
|
/**
|
|
* tcp_update_seqack_from_tap() - ACK number from tap and related flags/counters
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
* @seq Current ACK sequence, host order
|
|
*/
|
|
static void tcp_update_seqack_from_tap(const struct ctx *c,
|
|
struct tcp_tap_conn *conn, uint32_t seq)
|
|
{
|
|
if (seq == conn->seq_to_tap)
|
|
conn_flag(c, conn, ~ACK_FROM_TAP_DUE);
|
|
|
|
if (SEQ_GT(seq, conn->seq_ack_from_tap)) {
|
|
/* Forward progress, but more data to acknowledge: reschedule */
|
|
if (SEQ_LT(seq, conn->seq_to_tap))
|
|
conn_flag(c, conn, ACK_FROM_TAP_DUE);
|
|
|
|
conn->retrans = 0;
|
|
conn->seq_ack_from_tap = seq;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tcp_fill_flag_header() - Prepare header for flags-only segment (no payload)
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
* @flags: TCP flags: if not set, send segment only if ACK is due
|
|
* @th: TCP header to update
|
|
* @opts: buffer to store TCP option
|
|
* @optlen: size of the TCP option buffer
|
|
*
|
|
* Return: < 0 error code on connection reset,
|
|
* 0 if there is no flag to send
|
|
* 1 otherwise
|
|
*/
|
|
static int tcp_fill_flag_header(struct ctx *c, struct tcp_tap_conn *conn,
|
|
int flags, struct tcphdr *th, char *opts,
|
|
size_t *optlen)
|
|
{
|
|
uint32_t prev_ack_to_tap = conn->seq_ack_to_tap;
|
|
uint32_t prev_wnd_to_tap = conn->wnd_to_tap;
|
|
struct tcp_info tinfo = { 0 };
|
|
socklen_t sl = sizeof(tinfo);
|
|
int s = conn->sock;
|
|
|
|
if (SEQ_GE(conn->seq_ack_to_tap, conn->seq_from_tap) &&
|
|
!flags && conn->wnd_to_tap)
|
|
return 0;
|
|
|
|
if (getsockopt(s, SOL_TCP, TCP_INFO, &tinfo, &sl)) {
|
|
conn_event(c, conn, CLOSED);
|
|
return -ECONNRESET;
|
|
}
|
|
|
|
#ifdef HAS_SND_WND
|
|
if (!c->tcp.kernel_snd_wnd && tinfo.tcpi_snd_wnd)
|
|
c->tcp.kernel_snd_wnd = 1;
|
|
#endif
|
|
|
|
if (!(conn->flags & LOCAL))
|
|
tcp_rtt_dst_check(conn, &tinfo);
|
|
|
|
if (!tcp_update_seqack_wnd(c, conn, flags, &tinfo) && !flags)
|
|
return 0;
|
|
|
|
if (flags & SYN) {
|
|
int mss;
|
|
|
|
/* Options: MSS, NOP and window scale (8 bytes) */
|
|
*optlen = OPT_MSS_LEN + 1 + OPT_WS_LEN;
|
|
|
|
*opts++ = OPT_MSS;
|
|
*opts++ = OPT_MSS_LEN;
|
|
|
|
if (c->mtu == -1) {
|
|
mss = tinfo.tcpi_snd_mss;
|
|
} else {
|
|
mss = c->mtu - sizeof(struct tcphdr);
|
|
|
|
if (c->low_wmem &&
|
|
!(conn->flags & LOCAL) && !tcp_rtt_dst_low(conn))
|
|
mss = MIN(mss, PAGE_SIZE);
|
|
else if (mss > PAGE_SIZE)
|
|
mss = ROUND_DOWN(mss, PAGE_SIZE);
|
|
}
|
|
*(uint16_t *)opts = htons(MIN(USHRT_MAX, mss));
|
|
|
|
opts += OPT_MSS_LEN - 2;
|
|
|
|
conn->ws_to_tap = MIN(MAX_WS, tinfo.tcpi_snd_wscale);
|
|
|
|
*opts++ = OPT_NOP;
|
|
*opts++ = OPT_WS;
|
|
*opts++ = OPT_WS_LEN;
|
|
*opts++ = conn->ws_to_tap;
|
|
|
|
th->ack = !!(flags & ACK);
|
|
} else {
|
|
th->ack = !!(flags & (ACK | DUP_ACK)) ||
|
|
conn->seq_ack_to_tap != prev_ack_to_tap ||
|
|
!prev_wnd_to_tap;
|
|
}
|
|
|
|
th->doff = (sizeof(*th) + *optlen) / 4;
|
|
|
|
th->rst = !!(flags & RST);
|
|
th->syn = !!(flags & SYN);
|
|
th->fin = !!(flags & FIN);
|
|
|
|
if (th->ack) {
|
|
if (SEQ_GE(conn->seq_ack_to_tap, conn->seq_from_tap))
|
|
conn_flag(c, conn, ~ACK_TO_TAP_DUE);
|
|
else
|
|
conn_flag(c, conn, ACK_TO_TAP_DUE);
|
|
}
|
|
|
|
if (th->fin)
|
|
conn_flag(c, conn, ACK_FROM_TAP_DUE);
|
|
|
|
/* RFC 793, 3.1: "[...] and the first data octet is ISN+1." */
|
|
if (th->fin || th->syn)
|
|
conn->seq_to_tap++;
|
|
|
|
return 1;
|
|
}
|
|
|
|
static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags)
|
|
{
|
|
struct tcp_l2_flags_t *payload;
|
|
struct iovec *dup_iov;
|
|
struct iovec *iov;
|
|
struct tcphdr *th;
|
|
size_t optlen = 0;
|
|
size_t ip_len;
|
|
char *data;
|
|
int ret;
|
|
|
|
if (CONN_V4(conn)) {
|
|
iov = tcp4_l2_flags_iov[tcp4_l2_flags_buf_used++];
|
|
dup_iov = tcp4_l2_flags_iov[tcp4_l2_flags_buf_used];
|
|
} else {
|
|
iov = tcp6_l2_flags_iov[tcp6_l2_flags_buf_used++];
|
|
dup_iov = tcp6_l2_flags_iov[tcp6_l2_flags_buf_used];
|
|
}
|
|
payload = iov[TCP_IOV_PAYLOAD].iov_base;
|
|
th = &payload->th;
|
|
data = payload->opts;
|
|
|
|
ret = tcp_fill_flag_header(c, conn, flags, th, data, &optlen);
|
|
if (ret <= 0)
|
|
return ret;
|
|
|
|
if (CONN_V4(conn)) {
|
|
struct iphdr *iph = iov[TCP_IOV_IP].iov_base;
|
|
|
|
ip_len = tcp_fill_headers4(c, conn, iph, th, optlen, NULL,
|
|
conn->seq_to_tap);
|
|
} else {
|
|
struct ipv6hdr *ip6h = iov[TCP_IOV_IP].iov_base;
|
|
|
|
ip_len = tcp_fill_headers6(c, conn, ip6h, th, optlen,
|
|
conn->seq_to_tap);
|
|
}
|
|
iov[TCP_IOV_PAYLOAD].iov_len = ip_len;
|
|
|
|
if (flags & DUP_ACK) {
|
|
int i;
|
|
for (i = 0; i < TCP_IOV_NUM; i++) {
|
|
memcpy(dup_iov[i].iov_base, iov[i].iov_base,
|
|
iov[i].iov_len);
|
|
dup_iov[i].iov_len = iov[i].iov_len;
|
|
}
|
|
}
|
|
|
|
if (CONN_V4(conn)) {
|
|
if (flags & DUP_ACK)
|
|
tcp4_l2_flags_buf_used++;
|
|
|
|
if (tcp4_l2_flags_buf_used > TCP_FRAMES_MEM - 2)
|
|
tcp_l2_flags_buf_flush(c);
|
|
} else {
|
|
if (flags & DUP_ACK)
|
|
tcp6_l2_flags_buf_used++;
|
|
|
|
if (tcp6_l2_flags_buf_used > TCP_FRAMES_MEM - 2)
|
|
tcp_l2_flags_buf_flush(c);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_rst_do() - Reset a tap connection: send RST segment to tap, close socket
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
*/
|
|
static void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn)
|
|
{
|
|
if (conn->events == CLOSED)
|
|
return;
|
|
|
|
if (!tcp_send_flag(c, conn, RST))
|
|
conn_event(c, conn, CLOSED);
|
|
}
|
|
|
|
/**
|
|
* tcp_get_tap_ws() - Get Window Scaling option for connection from tap/guest
|
|
* @conn: Connection pointer
|
|
* @opts: Pointer to start of TCP options
|
|
* @optlen: Bytes in options: caller MUST ensure available length
|
|
*/
|
|
static void tcp_get_tap_ws(struct tcp_tap_conn *conn,
|
|
const char *opts, size_t optlen)
|
|
{
|
|
int ws = tcp_opt_get(opts, optlen, OPT_WS, NULL, NULL);
|
|
|
|
if (ws >= 0 && ws <= TCP_WS_MAX)
|
|
conn->ws_from_tap = ws;
|
|
else
|
|
conn->ws_from_tap = 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_tap_window_update() - Process an updated window from tap side
|
|
* @conn: Connection pointer
|
|
* @window: Window value, host order, unscaled
|
|
*/
|
|
static void tcp_tap_window_update(struct tcp_tap_conn *conn, unsigned wnd)
|
|
{
|
|
wnd = MIN(MAX_WINDOW, wnd << conn->ws_from_tap);
|
|
conn->wnd_from_tap = MIN(wnd >> conn->ws_from_tap, USHRT_MAX);
|
|
|
|
/* FIXME: reflect the tap-side receiver's window back to the sock-side
|
|
* sender by adjusting SO_RCVBUF? */
|
|
}
|
|
|
|
/**
|
|
* tcp_seq_init() - Calculate initial sequence number according to RFC 6528
|
|
* @c: Execution context
|
|
* @conn: TCP connection, with faddr, fport and eport populated
|
|
* @now: Current timestamp
|
|
*/
|
|
static void tcp_seq_init(const struct ctx *c, struct tcp_tap_conn *conn,
|
|
const struct timespec *now)
|
|
{
|
|
struct siphash_state state = SIPHASH_INIT(c->hash_secret);
|
|
union inany_addr aany;
|
|
uint64_t hash;
|
|
uint32_t ns;
|
|
|
|
if (CONN_V4(conn))
|
|
inany_from_af(&aany, AF_INET, &c->ip4.addr);
|
|
else
|
|
inany_from_af(&aany, AF_INET6, &c->ip6.addr);
|
|
|
|
inany_siphash_feed(&state, &conn->faddr);
|
|
inany_siphash_feed(&state, &aany);
|
|
hash = siphash_final(&state, 36,
|
|
(uint64_t)conn->fport << 16 | conn->eport);
|
|
|
|
/* 32ns ticks, overflows 32 bits every 137s */
|
|
ns = (now->tv_sec * 1000000000 + now->tv_nsec) >> 5;
|
|
|
|
conn->seq_to_tap = ((uint32_t)(hash >> 32) ^ (uint32_t)hash) + ns;
|
|
}
|
|
|
|
/**
|
|
* tcp_conn_pool_sock() - Get socket for new connection from pre-opened pool
|
|
* @pool: Pool of pre-opened sockets
|
|
*
|
|
* Return: socket number if available, negative code if pool is empty
|
|
*/
|
|
int tcp_conn_pool_sock(int pool[])
|
|
{
|
|
int s = -1, i;
|
|
|
|
for (i = 0; i < TCP_SOCK_POOL_SIZE; i++) {
|
|
SWAP(s, pool[i]);
|
|
if (s >= 0)
|
|
return s;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* tcp_conn_new_sock() - Open and prepare new socket for connection
|
|
* @c: Execution context
|
|
* @af: Address family
|
|
*
|
|
* Return: socket number on success, negative code if socket creation failed
|
|
*/
|
|
static int tcp_conn_new_sock(const struct ctx *c, sa_family_t af)
|
|
{
|
|
int s;
|
|
|
|
s = socket(af, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP);
|
|
|
|
if (s > FD_REF_MAX) {
|
|
close(s);
|
|
return -EIO;
|
|
}
|
|
|
|
if (s < 0)
|
|
return -errno;
|
|
|
|
tcp_sock_set_bufsize(c, s);
|
|
|
|
return s;
|
|
}
|
|
|
|
/**
|
|
* tcp_conn_sock() - Obtain a connectable socket in the host/init namespace
|
|
* @c: Execution context
|
|
* @af: Address family (AF_INET or AF_INET6)
|
|
*
|
|
* Return: Socket fd on success, -errno on failure
|
|
*/
|
|
int tcp_conn_sock(const struct ctx *c, sa_family_t af)
|
|
{
|
|
int *pool = af == AF_INET6 ? init_sock_pool6 : init_sock_pool4;
|
|
int s;
|
|
|
|
if ((s = tcp_conn_pool_sock(pool)) >= 0)
|
|
return s;
|
|
|
|
/* If the pool is empty we just open a new one without refilling the
|
|
* pool to keep latency down.
|
|
*/
|
|
if ((s = tcp_conn_new_sock(c, af)) >= 0)
|
|
return s;
|
|
|
|
err("TCP: Unable to open socket for new connection: %s",
|
|
strerror(-s));
|
|
return -1;
|
|
}
|
|
|
|
/**
|
|
* tcp_conn_tap_mss() - Get MSS value advertised by tap/guest
|
|
* @conn: Connection pointer
|
|
* @opts: Pointer to start of TCP options
|
|
* @optlen: Bytes in options: caller MUST ensure available length
|
|
*
|
|
* Return: clamped MSS value
|
|
*/
|
|
static uint16_t tcp_conn_tap_mss(const struct tcp_tap_conn *conn,
|
|
const char *opts, size_t optlen)
|
|
{
|
|
unsigned int mss;
|
|
int ret;
|
|
|
|
(void)conn; /* unused */
|
|
|
|
if ((ret = tcp_opt_get(opts, optlen, OPT_MSS, NULL, NULL)) < 0)
|
|
mss = MSS_DEFAULT;
|
|
else
|
|
mss = ret;
|
|
|
|
mss = MIN(MSS, mss);
|
|
|
|
return MIN(mss, USHRT_MAX);
|
|
}
|
|
|
|
/**
|
|
* tcp_bind_outbound() - Bind socket to outbound address and interface if given
|
|
* @c: Execution context
|
|
* @s: Outbound TCP socket
|
|
* @af: Address family
|
|
*/
|
|
static void tcp_bind_outbound(const struct ctx *c, int s, sa_family_t af)
|
|
{
|
|
if (af == AF_INET) {
|
|
if (!IN4_IS_ADDR_UNSPECIFIED(&c->ip4.addr_out)) {
|
|
struct sockaddr_in addr4 = {
|
|
.sin_family = AF_INET,
|
|
.sin_port = 0,
|
|
.sin_addr = c->ip4.addr_out,
|
|
};
|
|
|
|
if (bind(s, (struct sockaddr *)&addr4, sizeof(addr4))) {
|
|
debug("Can't bind IPv4 TCP socket address: %s",
|
|
strerror(errno));
|
|
}
|
|
}
|
|
|
|
if (*c->ip4.ifname_out) {
|
|
if (setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE,
|
|
c->ip4.ifname_out,
|
|
strlen(c->ip4.ifname_out))) {
|
|
debug("Can't bind IPv4 TCP socket to interface:"
|
|
" %s", strerror(errno));
|
|
}
|
|
}
|
|
} else if (af == AF_INET6) {
|
|
if (!IN6_IS_ADDR_UNSPECIFIED(&c->ip6.addr_out)) {
|
|
struct sockaddr_in6 addr6 = {
|
|
.sin6_family = AF_INET6,
|
|
.sin6_port = 0,
|
|
.sin6_addr = c->ip6.addr_out,
|
|
};
|
|
|
|
if (bind(s, (struct sockaddr *)&addr6, sizeof(addr6))) {
|
|
debug("Can't bind IPv6 TCP socket address: %s",
|
|
strerror(errno));
|
|
}
|
|
}
|
|
|
|
if (*c->ip6.ifname_out) {
|
|
if (setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE,
|
|
c->ip6.ifname_out,
|
|
strlen(c->ip6.ifname_out))) {
|
|
debug("Can't bind IPv6 TCP socket to interface:"
|
|
" %s", strerror(errno));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tcp_conn_from_tap() - Handle connection request (SYN segment) from tap
|
|
* @c: Execution context
|
|
* @af: Address family, AF_INET or AF_INET6
|
|
* @saddr: Source address, pointer to in_addr or in6_addr
|
|
* @daddr: Destination address, pointer to in_addr or in6_addr
|
|
* @th: TCP header from tap: caller MUST ensure it's there
|
|
* @opts: Pointer to start of options
|
|
* @optlen: Bytes in options: caller MUST ensure available length
|
|
* @now: Current timestamp
|
|
*/
|
|
static void tcp_conn_from_tap(struct ctx *c, sa_family_t af,
|
|
const void *saddr, const void *daddr,
|
|
const struct tcphdr *th, const char *opts,
|
|
size_t optlen, const struct timespec *now)
|
|
{
|
|
in_port_t srcport = ntohs(th->source);
|
|
in_port_t dstport = ntohs(th->dest);
|
|
struct sockaddr_in addr4 = {
|
|
.sin_family = AF_INET,
|
|
.sin_port = htons(dstport),
|
|
.sin_addr = *(struct in_addr *)daddr,
|
|
};
|
|
struct sockaddr_in6 addr6 = {
|
|
.sin6_family = AF_INET6,
|
|
.sin6_port = htons(dstport),
|
|
.sin6_addr = *(struct in6_addr *)daddr,
|
|
};
|
|
const struct sockaddr *sa;
|
|
struct tcp_tap_conn *conn;
|
|
union flow *flow;
|
|
int s = -1, mss;
|
|
socklen_t sl;
|
|
|
|
if (!(flow = flow_alloc()))
|
|
return;
|
|
|
|
if (af == AF_INET) {
|
|
if (IN4_IS_ADDR_UNSPECIFIED(saddr) ||
|
|
IN4_IS_ADDR_BROADCAST(saddr) ||
|
|
IN4_IS_ADDR_MULTICAST(saddr) || srcport == 0 ||
|
|
IN4_IS_ADDR_UNSPECIFIED(daddr) ||
|
|
IN4_IS_ADDR_BROADCAST(daddr) ||
|
|
IN4_IS_ADDR_MULTICAST(daddr) || dstport == 0) {
|
|
char sstr[INET_ADDRSTRLEN], dstr[INET_ADDRSTRLEN];
|
|
|
|
debug("Invalid endpoint in TCP SYN: %s:%hu -> %s:%hu",
|
|
inet_ntop(AF_INET, saddr, sstr, sizeof(sstr)),
|
|
srcport,
|
|
inet_ntop(AF_INET, daddr, dstr, sizeof(dstr)),
|
|
dstport);
|
|
goto cancel;
|
|
}
|
|
} else if (af == AF_INET6) {
|
|
if (IN6_IS_ADDR_UNSPECIFIED(saddr) ||
|
|
IN6_IS_ADDR_MULTICAST(saddr) || srcport == 0 ||
|
|
IN6_IS_ADDR_UNSPECIFIED(daddr) ||
|
|
IN6_IS_ADDR_MULTICAST(daddr) || dstport == 0) {
|
|
char sstr[INET6_ADDRSTRLEN], dstr[INET6_ADDRSTRLEN];
|
|
|
|
debug("Invalid endpoint in TCP SYN: %s:%hu -> %s:%hu",
|
|
inet_ntop(AF_INET6, saddr, sstr, sizeof(sstr)),
|
|
srcport,
|
|
inet_ntop(AF_INET6, daddr, dstr, sizeof(dstr)),
|
|
dstport);
|
|
goto cancel;
|
|
}
|
|
}
|
|
|
|
if ((s = tcp_conn_sock(c, af)) < 0)
|
|
goto cancel;
|
|
|
|
if (!c->no_map_gw) {
|
|
if (af == AF_INET && IN4_ARE_ADDR_EQUAL(daddr, &c->ip4.gw))
|
|
addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
|
|
if (af == AF_INET6 && IN6_ARE_ADDR_EQUAL(daddr, &c->ip6.gw))
|
|
addr6.sin6_addr = in6addr_loopback;
|
|
}
|
|
|
|
if (af == AF_INET6 && IN6_IS_ADDR_LINKLOCAL(&addr6.sin6_addr)) {
|
|
struct sockaddr_in6 addr6_ll = {
|
|
.sin6_family = AF_INET6,
|
|
.sin6_addr = c->ip6.addr_ll,
|
|
.sin6_scope_id = c->ifi6,
|
|
};
|
|
if (bind(s, (struct sockaddr *)&addr6_ll, sizeof(addr6_ll)))
|
|
goto cancel;
|
|
}
|
|
|
|
conn = FLOW_START(flow, FLOW_TCP, tcp, TAPSIDE);
|
|
conn->sock = s;
|
|
conn->timer = -1;
|
|
conn_event(c, conn, TAP_SYN_RCVD);
|
|
|
|
conn->wnd_to_tap = WINDOW_DEFAULT;
|
|
|
|
mss = tcp_conn_tap_mss(conn, opts, optlen);
|
|
if (setsockopt(s, SOL_TCP, TCP_MAXSEG, &mss, sizeof(mss)))
|
|
flow_trace(conn, "failed to set TCP_MAXSEG on socket %i", s);
|
|
MSS_SET(conn, mss);
|
|
|
|
tcp_get_tap_ws(conn, opts, optlen);
|
|
|
|
/* RFC 7323, 2.2: first value is not scaled. Also, don't clamp yet, to
|
|
* avoid getting a zero scale just because we set a small window now.
|
|
*/
|
|
if (!(conn->wnd_from_tap = (htons(th->window) >> conn->ws_from_tap)))
|
|
conn->wnd_from_tap = 1;
|
|
|
|
inany_from_af(&conn->faddr, af, daddr);
|
|
|
|
if (af == AF_INET) {
|
|
sa = (struct sockaddr *)&addr4;
|
|
sl = sizeof(addr4);
|
|
} else {
|
|
sa = (struct sockaddr *)&addr6;
|
|
sl = sizeof(addr6);
|
|
}
|
|
|
|
conn->fport = dstport;
|
|
conn->eport = srcport;
|
|
|
|
conn->seq_init_from_tap = ntohl(th->seq);
|
|
conn->seq_from_tap = conn->seq_init_from_tap + 1;
|
|
conn->seq_ack_to_tap = conn->seq_from_tap;
|
|
|
|
tcp_seq_init(c, conn, now);
|
|
conn->seq_ack_from_tap = conn->seq_to_tap;
|
|
|
|
tcp_hash_insert(c, conn);
|
|
|
|
if (!bind(s, sa, sl)) {
|
|
tcp_rst(c, conn); /* Nobody is listening then */
|
|
return;
|
|
}
|
|
if (errno != EADDRNOTAVAIL && errno != EACCES)
|
|
conn_flag(c, conn, LOCAL);
|
|
|
|
if ((af == AF_INET && !IN4_IS_ADDR_LOOPBACK(&addr4.sin_addr)) ||
|
|
(af == AF_INET6 && !IN6_IS_ADDR_LOOPBACK(&addr6.sin6_addr) &&
|
|
!IN6_IS_ADDR_LINKLOCAL(&addr6.sin6_addr)))
|
|
tcp_bind_outbound(c, s, af);
|
|
|
|
if (connect(s, sa, sl)) {
|
|
if (errno != EINPROGRESS) {
|
|
tcp_rst(c, conn);
|
|
return;
|
|
}
|
|
|
|
tcp_get_sndbuf(conn);
|
|
} else {
|
|
tcp_get_sndbuf(conn);
|
|
|
|
if (tcp_send_flag(c, conn, SYN | ACK))
|
|
return;
|
|
|
|
conn_event(c, conn, TAP_SYN_ACK_SENT);
|
|
}
|
|
|
|
tcp_epoll_ctl(c, conn);
|
|
return;
|
|
|
|
cancel:
|
|
if (s >= 0)
|
|
close(s);
|
|
flow_alloc_cancel(flow);
|
|
}
|
|
|
|
/**
|
|
* tcp_sock_consume() - Consume (discard) data from buffer
|
|
* @conn: Connection pointer
|
|
* @ack_seq: ACK sequence, host order
|
|
*
|
|
* Return: 0 on success, negative error code from recv() on failure
|
|
*/
|
|
#ifdef VALGRIND
|
|
/* valgrind doesn't realise that passing a NULL buffer to recv() is ok if using
|
|
* MSG_TRUNC. We have a suppression for this in the tests, but it relies on
|
|
* valgrind being able to see the tcp_sock_consume() stack frame, which it won't
|
|
* if this gets inlined. This has a single caller making it a likely inlining
|
|
* candidate, and certain compiler versions will do so even at -O0.
|
|
*/
|
|
__attribute__((noinline))
|
|
#endif /* VALGRIND */
|
|
static int tcp_sock_consume(const struct tcp_tap_conn *conn, uint32_t ack_seq)
|
|
{
|
|
/* Simply ignore out-of-order ACKs: we already consumed the data we
|
|
* needed from the buffer, and we won't rewind back to a lower ACK
|
|
* sequence.
|
|
*/
|
|
if (SEQ_LE(ack_seq, conn->seq_ack_from_tap))
|
|
return 0;
|
|
|
|
/* cppcheck-suppress [nullPointer, unmatchedSuppression] */
|
|
if (recv(conn->sock, NULL, ack_seq - conn->seq_ack_from_tap,
|
|
MSG_DONTWAIT | MSG_TRUNC) < 0)
|
|
return -errno;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_data_to_tap() - Finalise (queue) highest-numbered scatter-gather buffer
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
* @plen: Payload length at L4
|
|
* @no_csum: Don't compute IPv4 checksum, use the one from previous buffer
|
|
* @seq: Sequence number to be sent
|
|
*/
|
|
static void tcp_data_to_tap(const struct ctx *c, struct tcp_tap_conn *conn,
|
|
ssize_t plen, int no_csum, uint32_t seq)
|
|
{
|
|
uint32_t *seq_update = &conn->seq_to_tap;
|
|
struct iovec *iov;
|
|
|
|
if (CONN_V4(conn)) {
|
|
struct iovec *iov_prev = tcp4_l2_iov[tcp4_l2_buf_used - 1];
|
|
const uint16_t *check = NULL;
|
|
|
|
if (no_csum) {
|
|
struct iphdr *iph = iov_prev[TCP_IOV_IP].iov_base;
|
|
check = &iph->check;
|
|
}
|
|
|
|
tcp4_l2_buf_seq_update[tcp4_l2_buf_used].seq = seq_update;
|
|
tcp4_l2_buf_seq_update[tcp4_l2_buf_used].len = plen;
|
|
|
|
iov = tcp4_l2_iov[tcp4_l2_buf_used++];
|
|
iov[TCP_IOV_PAYLOAD].iov_len = tcp_fill_headers4(c, conn,
|
|
iov[TCP_IOV_IP].iov_base,
|
|
iov[TCP_IOV_PAYLOAD].iov_base,
|
|
plen, check, seq);
|
|
|
|
if (tcp4_l2_buf_used > TCP_FRAMES_MEM - 1)
|
|
tcp_l2_data_buf_flush(c);
|
|
} else if (CONN_V6(conn)) {
|
|
tcp6_l2_buf_seq_update[tcp6_l2_buf_used].seq = seq_update;
|
|
tcp6_l2_buf_seq_update[tcp6_l2_buf_used].len = plen;
|
|
|
|
iov = tcp6_l2_iov[tcp6_l2_buf_used++];
|
|
iov[TCP_IOV_PAYLOAD].iov_len = tcp_fill_headers6(c, conn,
|
|
iov[TCP_IOV_IP].iov_base,
|
|
iov[TCP_IOV_PAYLOAD].iov_base,
|
|
plen, seq);
|
|
|
|
if (tcp6_l2_buf_used > TCP_FRAMES_MEM - 1)
|
|
tcp_l2_data_buf_flush(c);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tcp_data_from_sock() - Handle new data from socket, queue to tap, in window
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
*
|
|
* Return: negative on connection reset, 0 otherwise
|
|
*
|
|
* #syscalls recvmsg
|
|
*/
|
|
static int tcp_data_from_sock(struct ctx *c, struct tcp_tap_conn *conn)
|
|
{
|
|
uint32_t wnd_scaled = conn->wnd_from_tap << conn->ws_from_tap;
|
|
int fill_bufs, send_bufs = 0, last_len, iov_rem = 0;
|
|
int sendlen, len, plen, v4 = CONN_V4(conn);
|
|
int s = conn->sock, i, ret = 0;
|
|
struct msghdr mh_sock = { 0 };
|
|
uint16_t mss = MSS_GET(conn);
|
|
uint32_t already_sent, seq;
|
|
struct iovec *iov;
|
|
|
|
already_sent = conn->seq_to_tap - conn->seq_ack_from_tap;
|
|
|
|
if (SEQ_LT(already_sent, 0)) {
|
|
/* RFC 761, section 2.1. */
|
|
flow_trace(conn, "ACK sequence gap: ACK for %u, sent: %u",
|
|
conn->seq_ack_from_tap, conn->seq_to_tap);
|
|
conn->seq_to_tap = conn->seq_ack_from_tap;
|
|
already_sent = 0;
|
|
}
|
|
|
|
if (!wnd_scaled || already_sent >= wnd_scaled) {
|
|
conn_flag(c, conn, STALLED);
|
|
conn_flag(c, conn, ACK_FROM_TAP_DUE);
|
|
return 0;
|
|
}
|
|
|
|
/* Set up buffer descriptors we'll fill completely and partially. */
|
|
fill_bufs = DIV_ROUND_UP(wnd_scaled - already_sent, mss);
|
|
if (fill_bufs > TCP_FRAMES) {
|
|
fill_bufs = TCP_FRAMES;
|
|
iov_rem = 0;
|
|
} else {
|
|
iov_rem = (wnd_scaled - already_sent) % mss;
|
|
}
|
|
|
|
mh_sock.msg_iov = iov_sock;
|
|
mh_sock.msg_iovlen = fill_bufs + 1;
|
|
|
|
iov_sock[0].iov_base = tcp_buf_discard;
|
|
iov_sock[0].iov_len = already_sent;
|
|
|
|
if (( v4 && tcp4_l2_buf_used + fill_bufs > TCP_FRAMES_MEM) ||
|
|
(!v4 && tcp6_l2_buf_used + fill_bufs > TCP_FRAMES_MEM)) {
|
|
tcp_l2_data_buf_flush(c);
|
|
|
|
/* Silence Coverity CWE-125 false positive */
|
|
tcp4_l2_buf_used = tcp6_l2_buf_used = 0;
|
|
}
|
|
|
|
for (i = 0, iov = iov_sock + 1; i < fill_bufs; i++, iov++) {
|
|
if (v4)
|
|
iov->iov_base = &tcp4_l2_payload[tcp4_l2_buf_used + i].data;
|
|
else
|
|
iov->iov_base = &tcp6_l2_payload[tcp6_l2_buf_used + i].data;
|
|
iov->iov_len = mss;
|
|
}
|
|
if (iov_rem)
|
|
iov_sock[fill_bufs].iov_len = iov_rem;
|
|
|
|
/* Receive into buffers, don't dequeue until acknowledged by guest. */
|
|
do
|
|
len = recvmsg(s, &mh_sock, MSG_PEEK);
|
|
while (len < 0 && errno == EINTR);
|
|
|
|
if (len < 0)
|
|
goto err;
|
|
|
|
if (!len) {
|
|
if ((conn->events & (SOCK_FIN_RCVD | TAP_FIN_SENT)) == SOCK_FIN_RCVD) {
|
|
if ((ret = tcp_send_flag(c, conn, FIN | ACK))) {
|
|
tcp_rst(c, conn);
|
|
return ret;
|
|
}
|
|
|
|
conn_event(c, conn, TAP_FIN_SENT);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
sendlen = len - already_sent;
|
|
if (sendlen <= 0) {
|
|
conn_flag(c, conn, STALLED);
|
|
return 0;
|
|
}
|
|
|
|
conn_flag(c, conn, ~STALLED);
|
|
|
|
send_bufs = DIV_ROUND_UP(sendlen, mss);
|
|
last_len = sendlen - (send_bufs - 1) * mss;
|
|
|
|
/* Likely, some new data was acked too. */
|
|
tcp_update_seqack_wnd(c, conn, 0, NULL);
|
|
|
|
/* Finally, queue to tap */
|
|
plen = mss;
|
|
seq = conn->seq_to_tap;
|
|
for (i = 0; i < send_bufs; i++) {
|
|
int no_csum = i && i != send_bufs - 1 && tcp4_l2_buf_used;
|
|
|
|
if (i == send_bufs - 1)
|
|
plen = last_len;
|
|
|
|
tcp_data_to_tap(c, conn, plen, no_csum, seq);
|
|
seq += plen;
|
|
}
|
|
|
|
conn_flag(c, conn, ACK_FROM_TAP_DUE);
|
|
|
|
return 0;
|
|
|
|
err:
|
|
if (errno != EAGAIN && errno != EWOULDBLOCK) {
|
|
ret = -errno;
|
|
tcp_rst(c, conn);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* tcp_data_from_tap() - tap/guest data for established connection
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
* @p: Pool of TCP packets, with TCP headers
|
|
* @idx: Index of first data packet in pool
|
|
*
|
|
* #syscalls sendmsg
|
|
*
|
|
* Return: count of consumed packets
|
|
*/
|
|
static int tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
|
|
const struct pool *p, int idx)
|
|
{
|
|
int i, iov_i, ack = 0, fin = 0, retr = 0, keep = -1, partial_send = 0;
|
|
uint16_t max_ack_seq_wnd = conn->wnd_from_tap;
|
|
uint32_t max_ack_seq = conn->seq_ack_from_tap;
|
|
uint32_t seq_from_tap = conn->seq_from_tap;
|
|
struct msghdr mh = { .msg_iov = tcp_iov };
|
|
size_t len;
|
|
ssize_t n;
|
|
|
|
if (conn->events == CLOSED)
|
|
return p->count - idx;
|
|
|
|
ASSERT(conn->events & ESTABLISHED);
|
|
|
|
for (i = idx, iov_i = 0; i < (int)p->count; i++) {
|
|
uint32_t seq, seq_offset, ack_seq;
|
|
const struct tcphdr *th;
|
|
char *data;
|
|
size_t off;
|
|
|
|
th = packet_get(p, i, 0, sizeof(*th), &len);
|
|
if (!th)
|
|
return -1;
|
|
len += sizeof(*th);
|
|
|
|
off = th->doff * 4UL;
|
|
if (off < sizeof(*th) || off > len)
|
|
return -1;
|
|
|
|
if (th->rst) {
|
|
conn_event(c, conn, CLOSED);
|
|
return 1;
|
|
}
|
|
|
|
len -= off;
|
|
data = packet_get(p, i, off, len, NULL);
|
|
if (!data)
|
|
continue;
|
|
|
|
seq = ntohl(th->seq);
|
|
ack_seq = ntohl(th->ack_seq);
|
|
|
|
if (th->ack) {
|
|
ack = 1;
|
|
|
|
if (SEQ_GE(ack_seq, conn->seq_ack_from_tap) &&
|
|
SEQ_GE(ack_seq, max_ack_seq)) {
|
|
/* Fast re-transmit */
|
|
retr = !len && !th->fin &&
|
|
ack_seq == max_ack_seq &&
|
|
ntohs(th->window) == max_ack_seq_wnd;
|
|
|
|
max_ack_seq_wnd = ntohs(th->window);
|
|
max_ack_seq = ack_seq;
|
|
}
|
|
}
|
|
|
|
if (th->fin)
|
|
fin = 1;
|
|
|
|
if (!len)
|
|
continue;
|
|
|
|
seq_offset = seq_from_tap - seq;
|
|
/* Use data from this buffer only in these two cases:
|
|
*
|
|
* , seq_from_tap , seq_from_tap
|
|
* |--------| <-- len |--------| <-- len
|
|
* '----' <-- offset ' <-- offset
|
|
* ^ seq ^ seq
|
|
* (offset >= 0, seq + len > seq_from_tap)
|
|
*
|
|
* discard in these two cases:
|
|
* , seq_from_tap , seq_from_tap
|
|
* |--------| <-- len |--------| <-- len
|
|
* '--------' <-- offset '-----| <- offset
|
|
* ^ seq ^ seq
|
|
* (offset >= 0, seq + len <= seq_from_tap)
|
|
*
|
|
* keep, look for another buffer, then go back, in this case:
|
|
* , seq_from_tap
|
|
* |--------| <-- len
|
|
* '===' <-- offset
|
|
* ^ seq
|
|
* (offset < 0)
|
|
*/
|
|
if (SEQ_GE(seq_offset, 0) && SEQ_LE(seq + len, seq_from_tap))
|
|
continue;
|
|
|
|
if (SEQ_LT(seq_offset, 0)) {
|
|
if (keep == -1)
|
|
keep = i;
|
|
continue;
|
|
}
|
|
|
|
tcp_iov[iov_i].iov_base = data + seq_offset;
|
|
tcp_iov[iov_i].iov_len = len - seq_offset;
|
|
seq_from_tap += tcp_iov[iov_i].iov_len;
|
|
iov_i++;
|
|
|
|
if (keep == i)
|
|
keep = -1;
|
|
|
|
if (keep != -1)
|
|
i = keep - 1;
|
|
}
|
|
|
|
/* On socket flush failure, pretend there was no ACK, try again later */
|
|
if (ack && !tcp_sock_consume(conn, max_ack_seq))
|
|
tcp_update_seqack_from_tap(c, conn, max_ack_seq);
|
|
|
|
tcp_tap_window_update(conn, max_ack_seq_wnd);
|
|
|
|
if (retr) {
|
|
flow_trace(conn,
|
|
"fast re-transmit, ACK: %u, previous sequence: %u",
|
|
max_ack_seq, conn->seq_to_tap);
|
|
conn->seq_to_tap = max_ack_seq;
|
|
tcp_data_from_sock(c, conn);
|
|
}
|
|
|
|
if (!iov_i)
|
|
goto out;
|
|
|
|
mh.msg_iovlen = iov_i;
|
|
eintr:
|
|
n = sendmsg(conn->sock, &mh, MSG_DONTWAIT | MSG_NOSIGNAL);
|
|
if (n < 0) {
|
|
if (errno == EPIPE) {
|
|
/* Here's the wrap, said the tap.
|
|
* In my pocket, said the socket.
|
|
* Then swiftly looked away and left.
|
|
*/
|
|
conn->seq_from_tap = seq_from_tap;
|
|
tcp_send_flag(c, conn, ACK);
|
|
}
|
|
|
|
if (errno == EINTR)
|
|
goto eintr;
|
|
|
|
if (errno == EAGAIN || errno == EWOULDBLOCK) {
|
|
tcp_send_flag(c, conn, ACK_IF_NEEDED);
|
|
return p->count - idx;
|
|
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
if (n < (int)(seq_from_tap - conn->seq_from_tap)) {
|
|
partial_send = 1;
|
|
conn->seq_from_tap += n;
|
|
tcp_send_flag(c, conn, ACK_IF_NEEDED);
|
|
} else {
|
|
conn->seq_from_tap += n;
|
|
}
|
|
|
|
out:
|
|
if (keep != -1) {
|
|
/* We use an 8-bit approximation here: the associated risk is
|
|
* that we skip a duplicate ACK on 8-bit sequence number
|
|
* collision. Fast retransmit is a SHOULD in RFC 5681, 3.2.
|
|
*/
|
|
if (conn->seq_dup_ack_approx != (conn->seq_from_tap & 0xff)) {
|
|
conn->seq_dup_ack_approx = conn->seq_from_tap & 0xff;
|
|
tcp_send_flag(c, conn, DUP_ACK);
|
|
}
|
|
return p->count - idx;
|
|
}
|
|
|
|
if (ack && conn->events & TAP_FIN_SENT &&
|
|
conn->seq_ack_from_tap == conn->seq_to_tap)
|
|
conn_event(c, conn, TAP_FIN_ACKED);
|
|
|
|
if (fin && !partial_send) {
|
|
conn->seq_from_tap++;
|
|
|
|
conn_event(c, conn, TAP_FIN_RCVD);
|
|
} else {
|
|
tcp_send_flag(c, conn, ACK_IF_NEEDED);
|
|
}
|
|
|
|
return p->count - idx;
|
|
}
|
|
|
|
/**
|
|
* tcp_conn_from_sock_finish() - Complete connection setup after connect()
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
* @th: TCP header of SYN, ACK segment: caller MUST ensure it's there
|
|
* @opts: Pointer to start of options
|
|
* @optlen: Bytes in options: caller MUST ensure available length
|
|
*/
|
|
static void tcp_conn_from_sock_finish(struct ctx *c, struct tcp_tap_conn *conn,
|
|
const struct tcphdr *th,
|
|
const char *opts, size_t optlen)
|
|
{
|
|
tcp_tap_window_update(conn, ntohs(th->window));
|
|
tcp_get_tap_ws(conn, opts, optlen);
|
|
|
|
/* First value is not scaled */
|
|
if (!(conn->wnd_from_tap >>= conn->ws_from_tap))
|
|
conn->wnd_from_tap = 1;
|
|
|
|
MSS_SET(conn, tcp_conn_tap_mss(conn, opts, optlen));
|
|
|
|
conn->seq_init_from_tap = ntohl(th->seq) + 1;
|
|
conn->seq_from_tap = conn->seq_init_from_tap;
|
|
conn->seq_ack_to_tap = conn->seq_from_tap;
|
|
|
|
conn_event(c, conn, ESTABLISHED);
|
|
|
|
/* The client might have sent data already, which we didn't
|
|
* dequeue waiting for SYN,ACK from tap -- check now.
|
|
*/
|
|
tcp_data_from_sock(c, conn);
|
|
tcp_send_flag(c, conn, ACK);
|
|
}
|
|
|
|
/**
|
|
* tcp_tap_handler() - Handle packets from tap and state transitions
|
|
* @c: Execution context
|
|
* @pif: pif on which the packet is arriving
|
|
* @af: Address family, AF_INET or AF_INET6
|
|
* @saddr: Source address
|
|
* @daddr: Destination address
|
|
* @p: Pool of TCP packets, with TCP headers
|
|
* @idx: Index of first packet in pool to process
|
|
* @now: Current timestamp
|
|
*
|
|
* Return: count of consumed packets
|
|
*/
|
|
int tcp_tap_handler(struct ctx *c, uint8_t pif, sa_family_t af,
|
|
const void *saddr, const void *daddr,
|
|
const struct pool *p, int idx, const struct timespec *now)
|
|
{
|
|
struct tcp_tap_conn *conn;
|
|
const struct tcphdr *th;
|
|
size_t optlen, len;
|
|
const char *opts;
|
|
int ack_due = 0;
|
|
int count;
|
|
|
|
(void)pif;
|
|
|
|
th = packet_get(p, idx, 0, sizeof(*th), &len);
|
|
if (!th)
|
|
return 1;
|
|
len += sizeof(*th);
|
|
|
|
optlen = th->doff * 4UL - sizeof(*th);
|
|
/* Static checkers might fail to see this: */
|
|
optlen = MIN(optlen, ((1UL << 4) /* from doff width */ - 6) * 4UL);
|
|
opts = packet_get(p, idx, sizeof(*th), optlen, NULL);
|
|
|
|
conn = tcp_hash_lookup(c, af, daddr, ntohs(th->source), ntohs(th->dest));
|
|
|
|
/* New connection from tap */
|
|
if (!conn) {
|
|
if (opts && th->syn && !th->ack)
|
|
tcp_conn_from_tap(c, af, saddr, daddr, th,
|
|
opts, optlen, now);
|
|
return 1;
|
|
}
|
|
|
|
flow_trace(conn, "packet length %zu from tap", len);
|
|
|
|
if (th->rst) {
|
|
conn_event(c, conn, CLOSED);
|
|
return 1;
|
|
}
|
|
|
|
if (th->ack && !(conn->events & ESTABLISHED))
|
|
tcp_update_seqack_from_tap(c, conn, ntohl(th->ack_seq));
|
|
|
|
/* Establishing connection from socket */
|
|
if (conn->events & SOCK_ACCEPTED) {
|
|
if (th->syn && th->ack && !th->fin) {
|
|
tcp_conn_from_sock_finish(c, conn, th, opts, optlen);
|
|
return 1;
|
|
}
|
|
|
|
goto reset;
|
|
}
|
|
|
|
/* Establishing connection from tap */
|
|
if (conn->events & TAP_SYN_RCVD) {
|
|
if (!(conn->events & TAP_SYN_ACK_SENT))
|
|
goto reset;
|
|
|
|
conn_event(c, conn, ESTABLISHED);
|
|
|
|
if (th->fin) {
|
|
conn->seq_from_tap++;
|
|
|
|
shutdown(conn->sock, SHUT_WR);
|
|
tcp_send_flag(c, conn, ACK);
|
|
conn_event(c, conn, SOCK_FIN_SENT);
|
|
|
|
return 1;
|
|
}
|
|
|
|
if (!th->ack)
|
|
goto reset;
|
|
|
|
tcp_tap_window_update(conn, ntohs(th->window));
|
|
|
|
tcp_data_from_sock(c, conn);
|
|
|
|
if (p->count - idx == 1)
|
|
return 1;
|
|
}
|
|
|
|
/* Established connections not accepting data from tap */
|
|
if (conn->events & TAP_FIN_RCVD) {
|
|
tcp_update_seqack_from_tap(c, conn, ntohl(th->ack_seq));
|
|
|
|
if (conn->events & SOCK_FIN_RCVD &&
|
|
conn->seq_ack_from_tap == conn->seq_to_tap)
|
|
conn_event(c, conn, CLOSED);
|
|
|
|
return 1;
|
|
}
|
|
|
|
/* Established connections accepting data from tap */
|
|
count = tcp_data_from_tap(c, conn, p, idx);
|
|
if (count == -1)
|
|
goto reset;
|
|
|
|
conn_flag(c, conn, ~STALLED);
|
|
|
|
if (conn->seq_ack_to_tap != conn->seq_from_tap)
|
|
ack_due = 1;
|
|
|
|
if ((conn->events & TAP_FIN_RCVD) && !(conn->events & SOCK_FIN_SENT)) {
|
|
shutdown(conn->sock, SHUT_WR);
|
|
conn_event(c, conn, SOCK_FIN_SENT);
|
|
tcp_send_flag(c, conn, ACK);
|
|
ack_due = 0;
|
|
}
|
|
|
|
if (ack_due)
|
|
conn_flag(c, conn, ACK_TO_TAP_DUE);
|
|
|
|
return count;
|
|
|
|
reset:
|
|
/* Something's gone wrong, so reset the connection. We discard
|
|
* remaining packets in the batch, since they'd be invalidated when our
|
|
* RST is received, even if otherwise good.
|
|
*/
|
|
tcp_rst(c, conn);
|
|
return p->count - idx;
|
|
}
|
|
|
|
/**
|
|
* tcp_connect_finish() - Handle completion of connect() from EPOLLOUT event
|
|
* @c: Execution context
|
|
* @conn: Connection pointer
|
|
*/
|
|
static void tcp_connect_finish(struct ctx *c, struct tcp_tap_conn *conn)
|
|
{
|
|
socklen_t sl;
|
|
int so;
|
|
|
|
sl = sizeof(so);
|
|
if (getsockopt(conn->sock, SOL_SOCKET, SO_ERROR, &so, &sl) || so) {
|
|
tcp_rst(c, conn);
|
|
return;
|
|
}
|
|
|
|
if (tcp_send_flag(c, conn, SYN | ACK))
|
|
return;
|
|
|
|
conn_event(c, conn, TAP_SYN_ACK_SENT);
|
|
conn_flag(c, conn, ACK_FROM_TAP_DUE);
|
|
}
|
|
|
|
/**
|
|
* tcp_snat_inbound() - Translate source address for inbound data if needed
|
|
* @c: Execution context
|
|
* @addr: Source address of inbound packet/connection
|
|
*/
|
|
static void tcp_snat_inbound(const struct ctx *c, union inany_addr *addr)
|
|
{
|
|
struct in_addr *addr4 = inany_v4(addr);
|
|
|
|
if (addr4) {
|
|
if (IN4_IS_ADDR_LOOPBACK(addr4) ||
|
|
IN4_IS_ADDR_UNSPECIFIED(addr4) ||
|
|
IN4_ARE_ADDR_EQUAL(addr4, &c->ip4.addr_seen))
|
|
*addr4 = c->ip4.gw;
|
|
} else {
|
|
struct in6_addr *addr6 = &addr->a6;
|
|
|
|
if (IN6_IS_ADDR_LOOPBACK(addr6) ||
|
|
IN6_ARE_ADDR_EQUAL(addr6, &c->ip6.addr_seen) ||
|
|
IN6_ARE_ADDR_EQUAL(addr6, &c->ip6.addr)) {
|
|
if (IN6_IS_ADDR_LINKLOCAL(&c->ip6.gw))
|
|
*addr6 = c->ip6.gw;
|
|
else
|
|
*addr6 = c->ip6.addr_ll;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tcp_tap_conn_from_sock() - Initialize state for non-spliced connection
|
|
* @c: Execution context
|
|
* @dstport: Destination port for connection (host side)
|
|
* @flow: flow to initialise
|
|
* @s: Accepted socket
|
|
* @sa: Peer socket address (from accept())
|
|
* @now: Current timestamp
|
|
*/
|
|
static void tcp_tap_conn_from_sock(struct ctx *c, in_port_t dstport,
|
|
union flow *flow, int s,
|
|
const union sockaddr_inany *sa,
|
|
const struct timespec *now)
|
|
{
|
|
struct tcp_tap_conn *conn = FLOW_START(flow, FLOW_TCP, tcp, SOCKSIDE);
|
|
|
|
conn->sock = s;
|
|
conn->timer = -1;
|
|
conn->ws_to_tap = conn->ws_from_tap = 0;
|
|
conn_event(c, conn, SOCK_ACCEPTED);
|
|
|
|
inany_from_sockaddr(&conn->faddr, &conn->fport, sa);
|
|
conn->eport = dstport + c->tcp.fwd_in.delta[dstport];
|
|
|
|
tcp_snat_inbound(c, &conn->faddr);
|
|
|
|
tcp_seq_init(c, conn, now);
|
|
tcp_hash_insert(c, conn);
|
|
|
|
conn->seq_ack_from_tap = conn->seq_to_tap;
|
|
|
|
conn->wnd_from_tap = WINDOW_DEFAULT;
|
|
|
|
tcp_send_flag(c, conn, SYN);
|
|
conn_flag(c, conn, ACK_FROM_TAP_DUE);
|
|
|
|
tcp_get_sndbuf(conn);
|
|
}
|
|
|
|
/**
|
|
* tcp_listen_handler() - Handle new connection request from listening socket
|
|
* @c: Execution context
|
|
* @ref: epoll reference of listening socket
|
|
* @now: Current timestamp
|
|
*/
|
|
void tcp_listen_handler(struct ctx *c, union epoll_ref ref,
|
|
const struct timespec *now)
|
|
{
|
|
union sockaddr_inany sa;
|
|
socklen_t sl = sizeof(sa);
|
|
union flow *flow;
|
|
int s;
|
|
|
|
if (c->no_tcp || !(flow = flow_alloc()))
|
|
return;
|
|
|
|
s = accept4(ref.fd, &sa.sa, &sl, SOCK_NONBLOCK);
|
|
if (s < 0)
|
|
goto cancel;
|
|
|
|
if (sa.sa_family == AF_INET) {
|
|
const struct in_addr *addr = &sa.sa4.sin_addr;
|
|
in_port_t port = sa.sa4.sin_port;
|
|
|
|
if (IN4_IS_ADDR_UNSPECIFIED(addr) ||
|
|
IN4_IS_ADDR_BROADCAST(addr) ||
|
|
IN4_IS_ADDR_MULTICAST(addr) || port == 0) {
|
|
char str[INET_ADDRSTRLEN];
|
|
|
|
err("Invalid endpoint from TCP accept(): %s:%hu",
|
|
inet_ntop(AF_INET, addr, str, sizeof(str)), port);
|
|
goto cancel;
|
|
}
|
|
} else if (sa.sa_family == AF_INET6) {
|
|
const struct in6_addr *addr = &sa.sa6.sin6_addr;
|
|
in_port_t port = sa.sa6.sin6_port;
|
|
|
|
if (IN6_IS_ADDR_UNSPECIFIED(addr) ||
|
|
IN6_IS_ADDR_MULTICAST(addr) || port == 0) {
|
|
char str[INET6_ADDRSTRLEN];
|
|
|
|
err("Invalid endpoint from TCP accept(): %s:%hu",
|
|
inet_ntop(AF_INET6, addr, str, sizeof(str)), port);
|
|
goto cancel;
|
|
}
|
|
}
|
|
|
|
if (tcp_splice_conn_from_sock(c, ref.tcp_listen.pif,
|
|
ref.tcp_listen.port, flow, s, &sa))
|
|
return;
|
|
|
|
tcp_tap_conn_from_sock(c, ref.tcp_listen.port, flow, s, &sa, now);
|
|
return;
|
|
|
|
cancel:
|
|
flow_alloc_cancel(flow);
|
|
}
|
|
|
|
/**
|
|
* tcp_timer_handler() - timerfd events: close, send ACK, retransmit, or reset
|
|
* @c: Execution context
|
|
* @ref: epoll reference of timer (not connection)
|
|
*
|
|
* #syscalls timerfd_gettime
|
|
*/
|
|
void tcp_timer_handler(struct ctx *c, union epoll_ref ref)
|
|
{
|
|
struct itimerspec check_armed = { { 0 }, { 0 } };
|
|
struct tcp_tap_conn *conn = CONN(ref.flow);
|
|
|
|
if (c->no_tcp)
|
|
return;
|
|
|
|
/* We don't reset timers on ~ACK_FROM_TAP_DUE, ~ACK_TO_TAP_DUE. If the
|
|
* timer is currently armed, this event came from a previous setting,
|
|
* and we just set the timer to a new point in the future: discard it.
|
|
*/
|
|
timerfd_gettime(conn->timer, &check_armed);
|
|
if (check_armed.it_value.tv_sec || check_armed.it_value.tv_nsec)
|
|
return;
|
|
|
|
if (conn->flags & ACK_TO_TAP_DUE) {
|
|
tcp_send_flag(c, conn, ACK_IF_NEEDED);
|
|
tcp_timer_ctl(c, conn);
|
|
} else if (conn->flags & ACK_FROM_TAP_DUE) {
|
|
if (!(conn->events & ESTABLISHED)) {
|
|
flow_dbg(conn, "handshake timeout");
|
|
tcp_rst(c, conn);
|
|
} else if (CONN_HAS(conn, SOCK_FIN_SENT | TAP_FIN_ACKED)) {
|
|
flow_dbg(conn, "FIN timeout");
|
|
tcp_rst(c, conn);
|
|
} else if (conn->retrans == TCP_MAX_RETRANS) {
|
|
flow_dbg(conn, "retransmissions count exceeded");
|
|
tcp_rst(c, conn);
|
|
} else {
|
|
flow_dbg(conn, "ACK timeout, retry");
|
|
conn->retrans++;
|
|
conn->seq_to_tap = conn->seq_ack_from_tap;
|
|
tcp_data_from_sock(c, conn);
|
|
tcp_timer_ctl(c, conn);
|
|
}
|
|
} else {
|
|
struct itimerspec new = { { 0 }, { ACT_TIMEOUT, 0 } };
|
|
struct itimerspec old = { { 0 }, { 0 } };
|
|
|
|
/* Activity timeout: if it was already set, reset the
|
|
* connection, otherwise, it was a left-over from ACK_TO_TAP_DUE
|
|
* or ACK_FROM_TAP_DUE, so just set the long timeout in that
|
|
* case. This avoids having to preemptively reset the timer on
|
|
* ~ACK_TO_TAP_DUE or ~ACK_FROM_TAP_DUE.
|
|
*/
|
|
timerfd_settime(conn->timer, 0, &new, &old);
|
|
if (old.it_value.tv_sec == ACT_TIMEOUT) {
|
|
flow_dbg(conn, "activity timeout");
|
|
tcp_rst(c, conn);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tcp_sock_handler() - Handle new data from non-spliced socket
|
|
* @c: Execution context
|
|
* @ref: epoll reference
|
|
* @events: epoll events bitmap
|
|
*/
|
|
void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events)
|
|
{
|
|
struct tcp_tap_conn *conn = CONN(ref.flowside.flow);
|
|
|
|
ASSERT(conn->f.type == FLOW_TCP);
|
|
ASSERT(ref.flowside.side == SOCKSIDE);
|
|
|
|
if (conn->events == CLOSED)
|
|
return;
|
|
|
|
if (events & EPOLLERR) {
|
|
tcp_rst(c, conn);
|
|
return;
|
|
}
|
|
|
|
if ((conn->events & TAP_FIN_SENT) && (events & EPOLLHUP)) {
|
|
conn_event(c, conn, CLOSED);
|
|
return;
|
|
}
|
|
|
|
if (conn->events & ESTABLISHED) {
|
|
if (CONN_HAS(conn, SOCK_FIN_SENT | TAP_FIN_ACKED))
|
|
conn_event(c, conn, CLOSED);
|
|
|
|
if (events & (EPOLLRDHUP | EPOLLHUP))
|
|
conn_event(c, conn, SOCK_FIN_RCVD);
|
|
|
|
if (events & EPOLLIN)
|
|
tcp_data_from_sock(c, conn);
|
|
|
|
if (events & EPOLLOUT)
|
|
tcp_update_seqack_wnd(c, conn, 0, NULL);
|
|
|
|
return;
|
|
}
|
|
|
|
/* EPOLLHUP during handshake: reset */
|
|
if (events & EPOLLHUP) {
|
|
tcp_rst(c, conn);
|
|
return;
|
|
}
|
|
|
|
/* Data during handshake tap-side: check later */
|
|
if (conn->events & SOCK_ACCEPTED)
|
|
return;
|
|
|
|
if (conn->events == TAP_SYN_RCVD) {
|
|
if (events & EPOLLOUT)
|
|
tcp_connect_finish(c, conn);
|
|
/* Data? Check later */
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tcp_sock_init_af() - Initialise listening socket for a given af and port
|
|
* @c: Execution context
|
|
* @af: Address family to listen on
|
|
* @port: Port, host order
|
|
* @addr: Pointer to address for binding, NULL if not configured
|
|
* @ifname: Name of interface to bind to, NULL if not configured
|
|
*
|
|
* Return: fd for the new listening socket, negative error code on failure
|
|
*/
|
|
static int tcp_sock_init_af(const struct ctx *c, sa_family_t af, in_port_t port,
|
|
const void *addr, const char *ifname)
|
|
{
|
|
union tcp_listen_epoll_ref tref = {
|
|
.port = port,
|
|
.pif = PIF_HOST,
|
|
};
|
|
int s;
|
|
|
|
s = sock_l4(c, af, IPPROTO_TCP, addr, ifname, port, tref.u32);
|
|
|
|
if (c->tcp.fwd_in.mode == FWD_AUTO) {
|
|
if (af == AF_INET || af == AF_UNSPEC)
|
|
tcp_sock_init_ext[port][V4] = s < 0 ? -1 : s;
|
|
if (af == AF_INET6 || af == AF_UNSPEC)
|
|
tcp_sock_init_ext[port][V6] = s < 0 ? -1 : s;
|
|
}
|
|
|
|
if (s < 0)
|
|
return s;
|
|
|
|
tcp_sock_set_bufsize(c, s);
|
|
return s;
|
|
}
|
|
|
|
/**
|
|
* tcp_sock_init() - Create listening sockets for a given host ("inbound") port
|
|
* @c: Execution context
|
|
* @af: Address family to select a specific IP version, or AF_UNSPEC
|
|
* @addr: Pointer to address for binding, NULL if not configured
|
|
* @ifname: Name of interface to bind to, NULL if not configured
|
|
* @port: Port, host order
|
|
*
|
|
* Return: 0 on (partial) success, negative error code on (complete) failure
|
|
*/
|
|
int tcp_sock_init(const struct ctx *c, sa_family_t af, const void *addr,
|
|
const char *ifname, in_port_t port)
|
|
{
|
|
int r4 = FD_REF_MAX + 1, r6 = FD_REF_MAX + 1;
|
|
|
|
if (af == AF_UNSPEC && c->ifi4 && c->ifi6)
|
|
/* Attempt to get a dual stack socket */
|
|
if (tcp_sock_init_af(c, AF_UNSPEC, port, addr, ifname) >= 0)
|
|
return 0;
|
|
|
|
/* Otherwise create a socket per IP version */
|
|
if ((af == AF_INET || af == AF_UNSPEC) && c->ifi4)
|
|
r4 = tcp_sock_init_af(c, AF_INET, port, addr, ifname);
|
|
|
|
if ((af == AF_INET6 || af == AF_UNSPEC) && c->ifi6)
|
|
r6 = tcp_sock_init_af(c, AF_INET6, port, addr, ifname);
|
|
|
|
if (IN_INTERVAL(0, FD_REF_MAX, r4) || IN_INTERVAL(0, FD_REF_MAX, r6))
|
|
return 0;
|
|
|
|
return r4 < 0 ? r4 : r6;
|
|
}
|
|
|
|
/**
|
|
* tcp_ns_sock_init4() - Init socket to listen for outbound IPv4 connections
|
|
* @c: Execution context
|
|
* @port: Port, host order
|
|
*/
|
|
static void tcp_ns_sock_init4(const struct ctx *c, in_port_t port)
|
|
{
|
|
union tcp_listen_epoll_ref tref = {
|
|
.port = port,
|
|
.pif = PIF_SPLICE,
|
|
};
|
|
int s;
|
|
|
|
ASSERT(c->mode == MODE_PASTA);
|
|
|
|
s = sock_l4(c, AF_INET, IPPROTO_TCP, &in4addr_loopback, NULL, port,
|
|
tref.u32);
|
|
if (s >= 0)
|
|
tcp_sock_set_bufsize(c, s);
|
|
else
|
|
s = -1;
|
|
|
|
if (c->tcp.fwd_out.mode == FWD_AUTO)
|
|
tcp_sock_ns[port][V4] = s;
|
|
}
|
|
|
|
/**
|
|
* tcp_ns_sock_init6() - Init socket to listen for outbound IPv6 connections
|
|
* @c: Execution context
|
|
* @port: Port, host order
|
|
*/
|
|
static void tcp_ns_sock_init6(const struct ctx *c, in_port_t port)
|
|
{
|
|
union tcp_listen_epoll_ref tref = {
|
|
.port = port,
|
|
.pif = PIF_SPLICE,
|
|
};
|
|
int s;
|
|
|
|
ASSERT(c->mode == MODE_PASTA);
|
|
|
|
s = sock_l4(c, AF_INET6, IPPROTO_TCP, &in6addr_loopback, NULL, port,
|
|
tref.u32);
|
|
if (s >= 0)
|
|
tcp_sock_set_bufsize(c, s);
|
|
else
|
|
s = -1;
|
|
|
|
if (c->tcp.fwd_out.mode == FWD_AUTO)
|
|
tcp_sock_ns[port][V6] = s;
|
|
}
|
|
|
|
/**
|
|
* tcp_ns_sock_init() - Init socket to listen for spliced outbound connections
|
|
* @c: Execution context
|
|
* @port: Port, host order
|
|
*/
|
|
void tcp_ns_sock_init(const struct ctx *c, in_port_t port)
|
|
{
|
|
if (c->ifi4)
|
|
tcp_ns_sock_init4(c, port);
|
|
if (c->ifi6)
|
|
tcp_ns_sock_init6(c, port);
|
|
}
|
|
|
|
/**
|
|
* tcp_ns_socks_init() - Bind sockets in namespace for outbound connections
|
|
* @arg: Execution context
|
|
*
|
|
* Return: 0
|
|
*/
|
|
static int tcp_ns_socks_init(void *arg)
|
|
{
|
|
const struct ctx *c = (const struct ctx *)arg;
|
|
unsigned port;
|
|
|
|
ns_enter(c);
|
|
|
|
for (port = 0; port < NUM_PORTS; port++) {
|
|
if (!bitmap_isset(c->tcp.fwd_out.map, port))
|
|
continue;
|
|
|
|
tcp_ns_sock_init(c, port);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_sock_refill_pool() - Refill one pool of pre-opened sockets
|
|
* @c: Execution context
|
|
* @pool: Pool of sockets to refill
|
|
* @af: Address family to use
|
|
*
|
|
* Return: 0 on success, negative error code if there was at least one error
|
|
*/
|
|
int tcp_sock_refill_pool(const struct ctx *c, int pool[], sa_family_t af)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < TCP_SOCK_POOL_SIZE; i++) {
|
|
int fd;
|
|
|
|
if (pool[i] >= 0)
|
|
continue;
|
|
|
|
if ((fd = tcp_conn_new_sock(c, af)) < 0)
|
|
return fd;
|
|
|
|
pool[i] = fd;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_sock_refill_init() - Refill pools of pre-opened sockets in init ns
|
|
* @c: Execution context
|
|
*/
|
|
static void tcp_sock_refill_init(const struct ctx *c)
|
|
{
|
|
if (c->ifi4) {
|
|
int rc = tcp_sock_refill_pool(c, init_sock_pool4, AF_INET);
|
|
if (rc < 0)
|
|
warn("TCP: Error refilling IPv4 host socket pool: %s",
|
|
strerror(-rc));
|
|
}
|
|
if (c->ifi6) {
|
|
int rc = tcp_sock_refill_pool(c, init_sock_pool6, AF_INET6);
|
|
if (rc < 0)
|
|
warn("TCP: Error refilling IPv6 host socket pool: %s",
|
|
strerror(-rc));
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tcp_init() - Get initial sequence, hash secret, initialise per-socket data
|
|
* @c: Execution context
|
|
*
|
|
* Return: 0, doesn't return on failure
|
|
*/
|
|
int tcp_init(struct ctx *c)
|
|
{
|
|
unsigned b;
|
|
|
|
for (b = 0; b < TCP_HASH_TABLE_SIZE; b++)
|
|
tc_hash[b] = FLOW_SIDX_NONE;
|
|
|
|
if (c->ifi4)
|
|
tcp_sock4_iov_init(c);
|
|
|
|
if (c->ifi6)
|
|
tcp_sock6_iov_init(c);
|
|
|
|
memset(init_sock_pool4, 0xff, sizeof(init_sock_pool4));
|
|
memset(init_sock_pool6, 0xff, sizeof(init_sock_pool6));
|
|
memset(tcp_sock_init_ext, 0xff, sizeof(tcp_sock_init_ext));
|
|
memset(tcp_sock_ns, 0xff, sizeof(tcp_sock_ns));
|
|
|
|
tcp_sock_refill_init(c);
|
|
|
|
if (c->mode == MODE_PASTA) {
|
|
tcp_splice_init(c);
|
|
|
|
NS_CALL(tcp_ns_socks_init, c);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_port_rebind() - Rebind ports to match forward maps
|
|
* @c: Execution context
|
|
* @outbound: True to remap outbound forwards, otherwise inbound
|
|
*
|
|
* Must be called in namespace context if @outbound is true.
|
|
*/
|
|
static void tcp_port_rebind(struct ctx *c, bool outbound)
|
|
{
|
|
const uint8_t *fmap = outbound ? c->tcp.fwd_out.map : c->tcp.fwd_in.map;
|
|
const uint8_t *rmap = outbound ? c->tcp.fwd_in.map : c->tcp.fwd_out.map;
|
|
int (*socks)[IP_VERSIONS] = outbound ? tcp_sock_ns : tcp_sock_init_ext;
|
|
unsigned port;
|
|
|
|
for (port = 0; port < NUM_PORTS; port++) {
|
|
if (!bitmap_isset(fmap, port)) {
|
|
if (socks[port][V4] >= 0) {
|
|
close(socks[port][V4]);
|
|
socks[port][V4] = -1;
|
|
}
|
|
|
|
if (socks[port][V6] >= 0) {
|
|
close(socks[port][V6]);
|
|
socks[port][V6] = -1;
|
|
}
|
|
|
|
continue;
|
|
}
|
|
|
|
/* Don't loop back our own ports */
|
|
if (bitmap_isset(rmap, port))
|
|
continue;
|
|
|
|
if ((c->ifi4 && socks[port][V4] == -1) ||
|
|
(c->ifi6 && socks[port][V6] == -1)) {
|
|
if (outbound)
|
|
tcp_ns_sock_init(c, port);
|
|
else
|
|
tcp_sock_init(c, AF_UNSPEC, NULL, NULL, port);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* tcp_port_rebind_outbound() - Rebind ports in namespace
|
|
* @arg: Execution context
|
|
*
|
|
* Called with NS_CALL()
|
|
*
|
|
* Return: 0
|
|
*/
|
|
static int tcp_port_rebind_outbound(void *arg)
|
|
{
|
|
struct ctx *c = (struct ctx *)arg;
|
|
|
|
ns_enter(c);
|
|
tcp_port_rebind(c, true);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* tcp_timer() - Periodic tasks: port detection, closed connections, pool refill
|
|
* @c: Execution context
|
|
* @now: Current timestamp
|
|
*/
|
|
void tcp_timer(struct ctx *c, const struct timespec *now)
|
|
{
|
|
(void)now;
|
|
|
|
if (c->mode == MODE_PASTA) {
|
|
if (c->tcp.fwd_out.mode == FWD_AUTO) {
|
|
fwd_scan_ports_tcp(&c->tcp.fwd_out, &c->tcp.fwd_in);
|
|
NS_CALL(tcp_port_rebind_outbound, c);
|
|
}
|
|
|
|
if (c->tcp.fwd_in.mode == FWD_AUTO) {
|
|
fwd_scan_ports_tcp(&c->tcp.fwd_in, &c->tcp.fwd_out);
|
|
tcp_port_rebind(c, false);
|
|
}
|
|
}
|
|
|
|
tcp_sock_refill_init(c);
|
|
if (c->mode == MODE_PASTA)
|
|
tcp_splice_refill(c);
|
|
}
|