Mercurial > hg > nginx
view src/os/unix/ngx_udp_sendmsg_chain.c @ 8018:5119c8150478
Fixed runtime handling of systems without EPOLLRDHUP support.
In 7583:efd71d49bde0 (nginx 1.17.5) along with introduction of the
ioctl(FIONREAD) support proper handling of systems without EPOLLRDHUP
support in the kernel (but with EPOLLRDHUP in headers) was broken.
Before the change, rev->available was never set to 0 unless
ngx_use_epoll_rdhup was also set (that is, runtime test for EPOLLRDHUP
introduced in 6536:f7849bfb6d21 succeeded). After the change,
rev->available might reach 0 on systems without runtime EPOLLRDHUP
support, stopping further reading in ngx_readv_chain() and ngx_unix_recv().
And, if EOF happened to be already reported along with the last event,
it is not reported again by epoll_wait(), leading to connection hangs
and timeouts on such systems.
This affects Linux kernels before 2.6.17 if nginx was compiled
with newer headers, and, more importantly, emulation layers, such as
DigitalOcean's App Platform's / gVisor's epoll emulation layer.
Fix is to explicitly check ngx_use_epoll_rdhup before the corresponding
rev->pending_eof tests in ngx_readv_chain() and ngx_unix_recv().
author | Marcus Ball <marcus.ball@live.com> |
---|---|
date | Mon, 30 May 2022 02:38:07 +0300 |
parents | 0f6cc8f73744 |
children | 3108d4d668e4 ce6d9cf0f567 |
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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; }