passt/tcp.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

24 lines
634 B
C

#ifndef TCP_H
#define TCP_H
struct ctx;
void tcp_sock_handler(struct ctx *c, int s, uint32_t events);
int tcp_tap_handler(struct ctx *c, int af, void *addr,
struct tap_msg *msg, int count);
int tcp_sock_init(struct ctx *c);
void tcp_timer(struct ctx *c, struct timespec *ts);
/**
* struct tcp_ctx - Execution context for TCP routines
* @hash_secret: 128-bit secret for hash functions, ISN and hash table
* @fd_min: Lowest file descriptor number for TCP ever used
* @fd_max: Highest file descriptor number for TCP ever used
*/
struct tcp_ctx {
uint64_t hash_secret[2];
int fd_min;
int fd_max;
};
#endif /* TCP_H */