955dd3251c
Because packets sent on the tap interface will always be going to the guest/namespace, we more-or-less know what address they'll be going to. So we pre-fill this destination address in our header buffers for IPv4. We can't do the same for IPv6 because we could need either the global or link-local address for the guest. In future we're going to want more flexibility for the destination address, so this pre-filling will get in the way. Change the flow so we always fill in the IPv4 destination address for each packet, rather than prefilling it from proto_update_l2_buf(). In fact for TCP we already redundantly filled the destination for each packet anyway. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
309 lines
8.8 KiB
C
309 lines
8.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later
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* Copyright (c) 2021 Red Hat GmbH
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* Author: Stefano Brivio <sbrivio@redhat.com>
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*/
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#ifndef PASST_H
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#define PASST_H
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#define UNIX_SOCK_MAX 100
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#define UNIX_SOCK_PATH "/tmp/passt_%i.socket"
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/**
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* struct tap_msg - Generic message descriptor for arrays of messages
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* @pkt_buf_offset: Offset from @pkt_buf
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* @len: Message length, with L2 headers
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*/
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struct tap_msg {
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uint32_t pkt_buf_offset;
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uint16_t len;
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};
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/**
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* struct tap_l4_msg - Layer-4 message descriptor for protocol handlers
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* @pkt_buf_offset: Offset of message from @pkt_buf
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* @l4_len: Length of Layer-4 payload, host order
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*/
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struct tap_l4_msg {
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uint32_t pkt_buf_offset;
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uint16_t l4_len;
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};
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union epoll_ref;
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#include <stdbool.h>
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#include <assert.h>
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#include <sys/epoll.h>
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#include "packet.h"
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#include "icmp.h"
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#include "port_fwd.h"
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#include "tcp.h"
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#include "udp.h"
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/**
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* enum epoll_type - Different types of fds we poll over
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*/
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enum epoll_type {
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/* Special value to indicate an invalid type */
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EPOLL_TYPE_NONE = 0,
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/* Connected TCP sockets */
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EPOLL_TYPE_TCP,
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/* Listening TCP sockets */
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EPOLL_TYPE_TCP_LISTEN,
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/* timerfds used for TCP timers */
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EPOLL_TYPE_TCP_TIMER,
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/* UDP sockets */
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EPOLL_TYPE_UDP,
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/* IPv4 ICMP sockets */
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EPOLL_TYPE_ICMP,
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/* ICMPv6 sockets */
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EPOLL_TYPE_ICMPV6,
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/* inotify fd watching for end of netns (pasta) */
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EPOLL_TYPE_NSQUIT,
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/* tuntap character device */
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EPOLL_TYPE_TAP_PASTA,
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/* socket connected to qemu */
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EPOLL_TYPE_TAP_PASST,
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/* socket listening for qemu socket connections */
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EPOLL_TYPE_TAP_LISTEN,
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EPOLL_TYPE_MAX = EPOLL_TYPE_TAP_LISTEN,
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};
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/**
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* union epoll_ref - Breakdown of reference for epoll fd bookkeeping
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* @type: Type of fd (tells us what to do with events)
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* @fd: File descriptor number (implies < 2^24 total descriptors)
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* @tcp: TCP-specific reference part (connected sockets)
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* @tcp_listen: TCP-specific reference part (listening sockets)
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* @udp: UDP-specific reference part
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* @icmp: ICMP-specific reference part
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* @data: Data handled by protocol handlers
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* @u64: Opaque reference for epoll_ctl() and epoll_wait()
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*/
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union epoll_ref {
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struct {
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enum epoll_type type:8;
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#define FD_REF_BITS 24
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#define FD_REF_MAX MAX_FROM_BITS(FD_REF_BITS)
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int32_t fd:FD_REF_BITS;
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union {
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union tcp_epoll_ref tcp;
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union tcp_listen_epoll_ref tcp_listen;
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union udp_epoll_ref udp;
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union icmp_epoll_ref icmp;
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uint32_t data;
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};
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};
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uint64_t u64;
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};
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static_assert(sizeof(union epoll_ref) <= sizeof(union epoll_data),
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"epoll_ref must have same size as epoll_data");
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#define TAP_BUF_BYTES \
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ROUND_DOWN(((ETH_MAX_MTU + sizeof(uint32_t)) * 128), PAGE_SIZE)
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#define TAP_BUF_FILL (TAP_BUF_BYTES - ETH_MAX_MTU - sizeof(uint32_t))
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#define TAP_MSGS \
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DIV_ROUND_UP(TAP_BUF_BYTES, ETH_ZLEN - 2 * ETH_ALEN + sizeof(uint32_t))
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#define PKT_BUF_BYTES MAX(TAP_BUF_BYTES, 0)
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extern char pkt_buf [PKT_BUF_BYTES];
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extern char *epoll_type_str[];
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#define EPOLL_TYPE_STR(n) \
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(((uint8_t)(n) <= EPOLL_TYPE_MAX && epoll_type_str[(n)]) ? \
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epoll_type_str[(n)] : "?")
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#include <resolv.h> /* For MAXNS below */
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/**
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* struct fqdn - Representation of fully-qualified domain name
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* @n: Domain name string
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*/
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struct fqdn {
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char n[NS_MAXDNAME];
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};
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#include <net/if.h>
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#include <linux/un.h>
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enum passt_modes {
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MODE_PASST,
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MODE_PASTA,
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};
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/**
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* struct ip4_ctx - IPv4 execution context
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* @addr: IPv4 address for external, routable interface
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* @addr_seen: Latest IPv4 address seen as source from tap
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* @prefixlen: IPv4 prefix length (netmask)
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* @gw: Default IPv4 gateway, network order
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* @dns: DNS addresses for DHCP, zero-terminated, network order
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* @dns_match: Forward DNS query if sent to this address, network order
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* @dns_host: Use this DNS on the host for forwarding, network order
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* @addr_out: Optional source address for outbound traffic
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* @ifname_out: Optional interface name to bind outbound sockets to
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*/
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struct ip4_ctx {
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struct in_addr addr;
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struct in_addr addr_seen;
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int prefix_len;
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struct in_addr gw;
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struct in_addr dns[MAXNS + 1];
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struct in_addr dns_match;
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struct in_addr dns_host;
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struct in_addr addr_out;
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char ifname_out[IFNAMSIZ];
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};
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/**
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* struct ip6_ctx - IPv6 execution context
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* @addr: IPv6 address for external, routable interface
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* @addr_ll: Link-local IPv6 address on external, routable interface
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* @addr_seen: Latest IPv6 global/site address seen as source from tap
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* @addr_ll_seen: Latest IPv6 link-local address seen as source from tap
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* @gw: Default IPv6 gateway
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* @dns: DNS addresses for DHCPv6 and NDP, zero-terminated
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* @dns_match: Forward DNS query if sent to this address
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* @dns_host: Use this DNS on the host for forwarding
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* @addr_out: Optional source address for outbound traffic
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* @ifname_out: Optional interface name to bind outbound sockets to
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*/
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struct ip6_ctx {
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struct in6_addr addr;
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struct in6_addr addr_ll;
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struct in6_addr addr_seen;
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struct in6_addr addr_ll_seen;
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struct in6_addr gw;
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struct in6_addr dns[MAXNS + 1];
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struct in6_addr dns_match;
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struct in6_addr dns_host;
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struct in6_addr addr_out;
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char ifname_out[IFNAMSIZ];
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};
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#include <netinet/if_ether.h>
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/**
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* struct ctx - Execution context
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* @mode: Operation mode, qemu/UNIX domain socket or namespace/tap
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* @debug: Enable debug mode
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* @trace: Enable tracing (extra debug) mode
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* @quiet: Don't print informational messages
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* @foreground: Run in foreground, don't log to stderr by default
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* @force_stderr: Force logging to stderr
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* @nofile: Maximum number of open files (ulimit -n)
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* @sock_path: Path for UNIX domain socket
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* @pcap: Path for packet capture file
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* @pid_file: Path to PID file, empty string if not configured
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* @pasta_netns_fd: File descriptor for network namespace in pasta mode
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* @no_netns_quit: In pasta mode, don't exit if fs-bound namespace is gone
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* @netns_base: Base name for fs-bound namespace, if any, in pasta mode
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* @netns_dir: Directory of fs-bound namespace, if any, in pasta mode
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* @proc_net_tcp: Stored handles for /proc/net/tcp{,6} in init and ns
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* @proc_net_udp: Stored handles for /proc/net/udp{,6} in init and ns
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* @epollfd: File descriptor for epoll instance
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* @fd_tap_listen: File descriptor for listening AF_UNIX socket, if any
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* @fd_tap: AF_UNIX socket, tuntap device, or pre-opened socket
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* @mac: Host MAC address
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* @mac_guest: MAC address of guest or namespace, seen or configured
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* @ifi4: Index of template interface for IPv4, 0 if IPv4 disabled
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* @ip: IPv4 configuration
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* @dns_search: DNS search list
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* @ifi6: Index of template interface for IPv6, 0 if IPv6 disabled
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* @ip6: IPv6 configuration
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* @pasta_ifn: Name of namespace interface for pasta
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* @pasta_ifi: Index of namespace interface for pasta
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* @pasta_conf_ns: Configure namespace after creating it
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* @no_copy_routes: Don't copy all routes when configuring target namespace
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* @no_copy_addrs: Don't copy all addresses when configuring namespace
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* @no_tcp: Disable TCP operation
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* @tcp: Context for TCP protocol handler
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* @no_tcp: Disable UDP operation
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* @udp: Context for UDP protocol handler
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* @no_icmp: Disable ICMP operation
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* @icmp: Context for ICMP protocol handler
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* @mtu: MTU passed via DHCP/NDP
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* @no_dns: Do not source/use DNS servers for any purpose
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* @no_dns_search: Do not source/use domain search lists for any purpose
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* @no_dhcp_dns: Do not assign any DNS server via DHCP/DHCPv6/NDP
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* @no_dhcp_dns_search: Do not assign any DNS domain search via DHCP/DHCPv6/NDP
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* @no_dhcp: Disable DHCP server
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* @no_dhcpv6: Disable DHCPv6 server
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* @no_ndp: Disable NDP handler altogether
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* @no_ra: Disable router advertisements
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* @no_map_gw: Don't map connections, untracked UDP to gateway to host
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* @low_wmem: Low probed net.core.wmem_max
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* @low_rmem: Low probed net.core.rmem_max
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*/
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struct ctx {
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enum passt_modes mode;
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int debug;
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int trace;
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int quiet;
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int foreground;
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int force_stderr;
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int nofile;
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char sock_path[UNIX_PATH_MAX];
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char pcap[PATH_MAX];
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char pid_file[PATH_MAX];
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int one_off;
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int pasta_netns_fd;
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int no_netns_quit;
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char netns_base[PATH_MAX];
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char netns_dir[PATH_MAX];
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int proc_net_tcp[IP_VERSIONS][2];
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int proc_net_udp[IP_VERSIONS][2];
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int epollfd;
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int fd_tap_listen;
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int fd_tap;
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unsigned char mac[ETH_ALEN];
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unsigned char mac_guest[ETH_ALEN];
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unsigned int ifi4;
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struct ip4_ctx ip4;
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struct fqdn dns_search[MAXDNSRCH];
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unsigned int ifi6;
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struct ip6_ctx ip6;
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char pasta_ifn[IF_NAMESIZE];
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unsigned int pasta_ifi;
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int pasta_conf_ns;
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int no_copy_routes;
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int no_copy_addrs;
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int no_tcp;
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struct tcp_ctx tcp;
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int no_udp;
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struct udp_ctx udp;
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int no_icmp;
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struct icmp_ctx icmp;
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int mtu;
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int no_dns;
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int no_dns_search;
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int no_dhcp_dns;
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int no_dhcp_dns_search;
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int no_dhcp;
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int no_dhcpv6;
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int no_ndp;
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int no_ra;
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int no_map_gw;
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int low_wmem;
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int low_rmem;
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};
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void proto_update_l2_buf(const unsigned char *eth_d,
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const unsigned char *eth_s);
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#endif /* PASST_H */
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