Mercurial > hg > nginx
view src/os/unix/ngx_udp_sendmsg_chain.c @ 9143:48691bab4474
QUIC: fixed probe-congestion deadlock.
When probe timeout expired while congestion window was exhausted, probe PINGs
could not be sent. As a result, lost packets could not be declared lost and
congestion window could not be freed for new packets. This deadlock
continued until connection idle timeout expiration.
Now PINGs are sent separately from the frame queue without congestion control,
as specified by RFC 9002, Section 7:
An endpoint MUST NOT send a packet if it would cause bytes_in_flight
(see Appendix B.2) to be larger than the congestion window, unless the
packet is sent on a PTO timer expiration (see Section 6.2) or when entering
recovery (see Section 7.3.2).
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Mon, 14 Aug 2023 08:28:30 +0400 |
parents | af5adec171b4 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> static ngx_chain_t *ngx_udp_output_chain_to_iovec(ngx_iovec_t *vec, ngx_chain_t *in, ngx_log_t *log); static ssize_t ngx_sendmsg_vec(ngx_connection_t *c, ngx_iovec_t *vec); ngx_chain_t * ngx_udp_unix_sendmsg_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit) { ssize_t n; off_t send; ngx_chain_t *cl; ngx_event_t *wev; ngx_iovec_t vec; struct iovec iovs[NGX_IOVS_PREALLOCATE]; wev = c->write; if (!wev->ready) { return in; } #if (NGX_HAVE_KQUEUE) if ((ngx_event_flags & NGX_USE_KQUEUE_EVENT) && wev->pending_eof) { (void) ngx_connection_error(c, wev->kq_errno, "kevent() reported about an closed connection"); wev->error = 1; return NGX_CHAIN_ERROR; } #endif /* the maximum limit size is the maximum size_t value - the page size */ if (limit == 0 || limit > (off_t) (NGX_MAX_SIZE_T_VALUE - ngx_pagesize)) { limit = NGX_MAX_SIZE_T_VALUE - ngx_pagesize; } send = 0; vec.iovs = iovs; vec.nalloc = NGX_IOVS_PREALLOCATE; for ( ;; ) { /* create the iovec and coalesce the neighbouring bufs */ cl = ngx_udp_output_chain_to_iovec(&vec, in, c->log); if (cl == NGX_CHAIN_ERROR) { return NGX_CHAIN_ERROR; } if (cl && cl->buf->in_file) { ngx_log_error(NGX_LOG_ALERT, c->log, 0, "file buf in sendmsg " "t:%d r:%d f:%d %p %p-%p %p %O-%O", cl->buf->temporary, cl->buf->recycled, cl->buf->in_file, cl->buf->start, cl->buf->pos, cl->buf->last, cl->buf->file, cl->buf->file_pos, cl->buf->file_last); ngx_debug_point(); return NGX_CHAIN_ERROR; } if (cl == in) { return in; } send += vec.size; n = ngx_sendmsg_vec(c, &vec); if (n == NGX_ERROR) { return NGX_CHAIN_ERROR; } if (n == NGX_AGAIN) { wev->ready = 0; return in; } c->sent += n; in = ngx_chain_update_sent(in, n); if (send >= limit || in == NULL) { return in; } } } static ngx_chain_t * ngx_udp_output_chain_to_iovec(ngx_iovec_t *vec, ngx_chain_t *in, ngx_log_t *log) { size_t total, size; u_char *prev; ngx_uint_t n, flush; ngx_chain_t *cl; struct iovec *iov; cl = in; iov = NULL; prev = NULL; total = 0; n = 0; flush = 0; for ( /* void */ ; in && !flush; in = in->next) { if (in->buf->flush || in->buf->last_buf) { flush = 1; } if (ngx_buf_special(in->buf)) { continue; } if (in->buf->in_file) { break; } if (!ngx_buf_in_memory(in->buf)) { ngx_log_error(NGX_LOG_ALERT, log, 0, "bad buf in output chain " "t:%d r:%d f:%d %p %p-%p %p %O-%O", in->buf->temporary, in->buf->recycled, in->buf->in_file, in->buf->start, in->buf->pos, in->buf->last, in->buf->file, in->buf->file_pos, in->buf->file_last); ngx_debug_point(); return NGX_CHAIN_ERROR; } size = in->buf->last - in->buf->pos; if (prev == in->buf->pos) { iov->iov_len += size; } else { if (n == vec->nalloc) { ngx_log_error(NGX_LOG_ALERT, log, 0, "too many parts in a datagram"); return NGX_CHAIN_ERROR; } iov = &vec->iovs[n++]; iov->iov_base = (void *) in->buf->pos; iov->iov_len = size; } prev = in->buf->pos + size; total += size; } if (!flush) { #if (NGX_SUPPRESS_WARN) vec->size = 0; vec->count = 0; #endif return cl; } /* zero-sized datagram; pretend to have at least 1 iov */ if (n == 0) { iov = &vec->iovs[n++]; iov->iov_base = NULL; iov->iov_len = 0; } vec->count = n; vec->size = total; return in; } static ssize_t ngx_sendmsg_vec(ngx_connection_t *c, ngx_iovec_t *vec) { struct msghdr msg; #if (NGX_HAVE_ADDRINFO_CMSG) struct cmsghdr *cmsg; u_char msg_control[CMSG_SPACE(sizeof(ngx_addrinfo_t))]; #endif ngx_memzero(&msg, sizeof(struct msghdr)); if (c->socklen) { msg.msg_name = c->sockaddr; msg.msg_namelen = c->socklen; } msg.msg_iov = vec->iovs; msg.msg_iovlen = vec->count; #if (NGX_HAVE_ADDRINFO_CMSG) if (c->listening && c->listening->wildcard && c->local_sockaddr) { msg.msg_control = msg_control; msg.msg_controllen = sizeof(msg_control); ngx_memzero(msg_control, sizeof(msg_control)); cmsg = CMSG_FIRSTHDR(&msg); msg.msg_controllen = ngx_set_srcaddr_cmsg(cmsg, c->local_sockaddr); } #endif return ngx_sendmsg(c, &msg, 0); } #if (NGX_HAVE_ADDRINFO_CMSG) size_t ngx_set_srcaddr_cmsg(struct cmsghdr *cmsg, struct sockaddr *local_sockaddr) { size_t len; #if (NGX_HAVE_IP_SENDSRCADDR) struct in_addr *addr; struct sockaddr_in *sin; #elif (NGX_HAVE_IP_PKTINFO) struct in_pktinfo *pkt; struct sockaddr_in *sin; #endif #if (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO) struct in6_pktinfo *pkt6; struct sockaddr_in6 *sin6; #endif #if (NGX_HAVE_IP_SENDSRCADDR) || (NGX_HAVE_IP_PKTINFO) if (local_sockaddr->sa_family == AF_INET) { cmsg->cmsg_level = IPPROTO_IP; #if (NGX_HAVE_IP_SENDSRCADDR) cmsg->cmsg_type = IP_SENDSRCADDR; cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); len = CMSG_SPACE(sizeof(struct in_addr)); sin = (struct sockaddr_in *) local_sockaddr; addr = (struct in_addr *) CMSG_DATA(cmsg); *addr = sin->sin_addr; #elif (NGX_HAVE_IP_PKTINFO) cmsg->cmsg_type = IP_PKTINFO; cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); len = CMSG_SPACE(sizeof(struct in_pktinfo)); sin = (struct sockaddr_in *) local_sockaddr; pkt = (struct in_pktinfo *) CMSG_DATA(cmsg); ngx_memzero(pkt, sizeof(struct in_pktinfo)); pkt->ipi_spec_dst = sin->sin_addr; #endif return len; } #endif #if (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO) if (local_sockaddr->sa_family == AF_INET6) { cmsg->cmsg_level = IPPROTO_IPV6; cmsg->cmsg_type = IPV6_PKTINFO; cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); len = CMSG_SPACE(sizeof(struct in6_pktinfo)); sin6 = (struct sockaddr_in6 *) local_sockaddr; pkt6 = (struct in6_pktinfo *) CMSG_DATA(cmsg); ngx_memzero(pkt6, sizeof(struct in6_pktinfo)); pkt6->ipi6_addr = sin6->sin6_addr; return len; } #endif return 0; } ngx_int_t ngx_get_srcaddr_cmsg(struct cmsghdr *cmsg, struct sockaddr *local_sockaddr) { #if (NGX_HAVE_IP_RECVDSTADDR) struct in_addr *addr; struct sockaddr_in *sin; #elif (NGX_HAVE_IP_PKTINFO) struct in_pktinfo *pkt; struct sockaddr_in *sin; #endif #if (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO) struct in6_pktinfo *pkt6; struct sockaddr_in6 *sin6; #endif #if (NGX_HAVE_IP_RECVDSTADDR) if (cmsg->cmsg_level == IPPROTO_IP && cmsg->cmsg_type == IP_RECVDSTADDR && local_sockaddr->sa_family == AF_INET) { addr = (struct in_addr *) CMSG_DATA(cmsg); sin = (struct sockaddr_in *) local_sockaddr; sin->sin_addr = *addr; return NGX_OK; } #elif (NGX_HAVE_IP_PKTINFO) if (cmsg->cmsg_level == IPPROTO_IP && cmsg->cmsg_type == IP_PKTINFO && local_sockaddr->sa_family == AF_INET) { pkt = (struct in_pktinfo *) CMSG_DATA(cmsg); sin = (struct sockaddr_in *) local_sockaddr; sin->sin_addr = pkt->ipi_addr; return NGX_OK; } #endif #if (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO) if (cmsg->cmsg_level == IPPROTO_IPV6 && cmsg->cmsg_type == IPV6_PKTINFO && local_sockaddr->sa_family == AF_INET6) { pkt6 = (struct in6_pktinfo *) CMSG_DATA(cmsg); sin6 = (struct sockaddr_in6 *) local_sockaddr; sin6->sin6_addr = pkt6->ipi6_addr; return NGX_OK; } #endif return NGX_DECLINED; } #endif ssize_t ngx_sendmsg(ngx_connection_t *c, struct msghdr *msg, int flags) { ssize_t n; ngx_err_t err; #if (NGX_DEBUG) size_t size; ngx_uint_t i; #endif eintr: n = sendmsg(c->fd, msg, flags); if (n == -1) { err = ngx_errno; switch (err) { case NGX_EAGAIN: ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err, "sendmsg() not ready"); return NGX_AGAIN; case NGX_EINTR: ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err, "sendmsg() was interrupted"); goto eintr; default: c->write->error = 1; ngx_connection_error(c, err, "sendmsg() failed"); return NGX_ERROR; } } #if (NGX_DEBUG) for (i = 0, size = 0; i < (size_t) msg->msg_iovlen; i++) { size += msg->msg_iov[i].iov_len; } ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "sendmsg: %z of %uz", n, size); #endif return n; }