passt/passt.h
Stefano Brivio 38b50dba47 passt: Spare some syscalls, add some optimisations from profiling
Avoid a bunch of syscalls on forwarding paths by:

- storing minimum and maximum file descriptor numbers for each
  protocol, fall back to SO_PROTOCOL query only on overlaps

- allocating a larger receive buffer -- this can result in more
  coalesced packets than sendmmsg() can take (UIO_MAXIOV, i.e. 1024),
  so make sure we don't exceed that within a single call to protocol
  tap handlers

- nesting the handling loop in tap_handler() in the receive loop,
  so that we have better chances of filling our receive buffer in
  fewer calls

- skipping the recvfrom() in the UDP handler on EPOLLERR -- there's
  nothing to be done in that case

and while at it:

- restore the 20ms timer interval for periodic (TCP) events, I
  accidentally changed that to 100ms in an earlier commit

- attempt using SO_ZEROCOPY for UDP -- if it's not available,
  sendmmsg() will succeed anyway

- fix the handling of the status code from sendmmsg(), if it fails,
  we'll try to discard the first message, hence return 1 from the
  UDP handler

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2021-04-23 22:22:37 +02:00

61 lines
1.4 KiB
C

#define UNIX_SOCK_PATH "/tmp/passt.socket"
/**
* struct tap_msg - Generic message descriptor for arrays of messages
* @start: Pointer to message start
* @l4_start: Pointer to L4 header
* @len: Message length, with L2 headers
* @l4_len: Message length, with L4 headers
*/
struct tap_msg {
char *start;
char *l4h;
size_t len;
size_t l4_len;
};
#include "icmp.h"
#include "tcp.h"
#include "udp.h"
/**
* struct ctx - Execution context
* @epollfd: file descriptor for epoll instance
* @fd_unix: AF_UNIX socket for tap file descriptor
* @v4: Enable IPv4 transport
* @mac: Host MAC address
* @mac_guest: Guest MAC address
* @addr4: IPv4 address for external, routable interface
* @mask4: IPv4 netmask, network order
* @gw4: Default IPv4 gateway, network order
* @dns4: IPv4 DNS address, network order
* @v6: Enable IPv6 transport
* @addr6: IPv6 address for external, routable interface
* @gw6: Default IPv6 gateway
* @dns4: IPv6 DNS address
* @ifn: Name of routable interface
*/
struct ctx {
int epollfd;
int fd_unix;
unsigned char mac[ETH_ALEN];
unsigned char mac_guest[ETH_ALEN];
int v4;
unsigned long addr4;
unsigned long mask4;
unsigned long gw4;
unsigned long dns4;
int v6;
struct in6_addr addr6;
struct in6_addr addr6_guest;
struct in6_addr gw6;
struct in6_addr dns6;
char ifn[IF_NAMESIZE];
struct icmp_ctx icmp;
struct tcp_ctx tcp;
struct tcp_ctx udp;
};