Mercurial > hg > nginx
view src/os/unix/ngx_udp_sendmsg_chain.c @ 6980:dbb0c854e308
Set UDP datagram source address (ticket #1239).
Previously, the source IP address of a response UDP datagram could differ from
the original datagram destination address. This could happen if the server UDP
socket is bound to a wildcard address and the network interface chosen to output
the response packet has a different default address than the destination address
of the original packet. For example, if two addresses from the same network are
configured on an interface.
Now source address is set explicitly if a response is sent for a server UDP
socket bound to a wildcard address.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Tue, 11 Apr 2017 16:41:53 +0300 |
parents | 56fc55e32f23 |
children | 8ce1a34f160b |
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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(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(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; } vec->count = n; vec->size = total; return in; } static ssize_t ngx_sendmsg(ngx_connection_t *c, ngx_iovec_t *vec) { ssize_t n; ngx_err_t err; struct msghdr msg; #if (NGX_HAVE_MSGHDR_MSG_CONTROL) #if (NGX_HAVE_IP_SENDSRCADDR) u_char msg_control[CMSG_SPACE(sizeof(struct in_addr))]; #elif (NGX_HAVE_IP_PKTINFO) u_char msg_control[CMSG_SPACE(sizeof(struct in_pktinfo))]; #endif #if (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO) u_char msg_control6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; #endif #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_MSGHDR_MSG_CONTROL) if (c->listening && c->listening->wildcard && c->local_sockaddr) { #if (NGX_HAVE_IP_SENDSRCADDR) if (c->local_sockaddr->sa_family == AF_INET) { struct cmsghdr *cmsg; struct in_addr *addr; struct sockaddr_in *sin; msg.msg_control = &msg_control; msg.msg_controllen = sizeof(msg_control); cmsg = CMSG_FIRSTHDR(&msg); cmsg->cmsg_level = IPPROTO_IP; cmsg->cmsg_type = IP_SENDSRCADDR; cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_addr)); sin = (struct sockaddr_in *) c->local_sockaddr; addr = (struct in_addr *) CMSG_DATA(cmsg); *addr = sin->sin_addr; } #elif (NGX_HAVE_IP_PKTINFO) if (c->local_sockaddr->sa_family == AF_INET) { struct cmsghdr *cmsg; struct in_pktinfo *pkt; struct sockaddr_in *sin; msg.msg_control = &msg_control; msg.msg_controllen = sizeof(msg_control); cmsg = CMSG_FIRSTHDR(&msg); cmsg->cmsg_level = IPPROTO_IP; cmsg->cmsg_type = IP_PKTINFO; cmsg->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo)); sin = (struct sockaddr_in *) c->local_sockaddr; pkt = (struct in_pktinfo *) CMSG_DATA(cmsg); ngx_memzero(pkt, sizeof(struct in_pktinfo)); pkt->ipi_spec_dst = sin->sin_addr; } #endif #if (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO) if (c->local_sockaddr->sa_family == AF_INET6) { struct cmsghdr *cmsg; struct in6_pktinfo *pkt6; struct sockaddr_in6 *sin6; msg.msg_control = &msg_control6; msg.msg_controllen = sizeof(msg_control6); cmsg = CMSG_FIRSTHDR(&msg); cmsg->cmsg_level = IPPROTO_IPV6; cmsg->cmsg_type = IPV6_PKTINFO; cmsg->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo)); sin6 = (struct sockaddr_in6 *) c->local_sockaddr; pkt6 = (struct in6_pktinfo *) CMSG_DATA(cmsg); ngx_memzero(pkt6, sizeof(struct in6_pktinfo)); pkt6->ipi6_addr = sin6->sin6_addr; } #endif } #endif eintr: n = sendmsg(c->fd, &msg, 0); ngx_log_debug2(NGX_LOG_DEBUG_EVENT, c->log, 0, "sendmsg: %z of %uz", n, vec->size); 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; } } return n; }