view src/event/ngx_event_udp.h @ 8895:457afc332c67

Stream: don't flush empty buffers created for read errors. When we generate the last_buf buffer for an UDP upstream recv error, it does not contain any data from the wire. ngx_stream_write_filter attempts to forward it anyways, which is incorrect (e.g., UDP upstream ECONNREFUSED will be translated to an empty packet). This happens because we mark the buffer as both 'flush' and 'last_buf', and ngx_stream_write_filter has special handling for flush with certain types of connections (see d127837c714f, 32b0ba4855a6). The flags are meant to be mutually exclusive, so the fix is to ensure that flush and last_buf are not set at the same time. Reproduction: stream { upstream unreachable { server 127.0.0.1:8880; } server { listen 127.0.0.1:8998 udp; proxy_pass unreachable; } } 1 0.000000000 127.0.0.1 → 127.0.0.1 UDP 47 45588 → 8998 Len=5 2 0.000166300 127.0.0.1 → 127.0.0.1 UDP 47 51149 → 8880 Len=5 3 0.000172600 127.0.0.1 → 127.0.0.1 ICMP 75 Destination unreachable (Port unreachable) 4 0.000202400 127.0.0.1 → 127.0.0.1 UDP 42 8998 → 45588 Len=0 Fixes d127837c714f.
author Aleksei Bavshin <a.bavshin@f5.com>
date Mon, 23 May 2022 11:29:44 -0700
parents 0f6cc8f73744
children ce6d9cf0f567
line wrap: on
line source


/*
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_EVENT_UDP_H_INCLUDED_
#define _NGX_EVENT_UDP_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>


#if !(NGX_WIN32)

#if ((NGX_HAVE_MSGHDR_MSG_CONTROL)                                            \
     && (NGX_HAVE_IP_SENDSRCADDR || NGX_HAVE_IP_RECVDSTADDR                   \
         || NGX_HAVE_IP_PKTINFO                                               \
         || (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO)))
#define NGX_HAVE_ADDRINFO_CMSG  1

#endif


#if (NGX_HAVE_ADDRINFO_CMSG)

typedef union {
#if (NGX_HAVE_IP_SENDSRCADDR || NGX_HAVE_IP_RECVDSTADDR)
    struct in_addr        addr;
#endif

#if (NGX_HAVE_IP_PKTINFO)
    struct in_pktinfo     pkt;
#endif

#if (NGX_HAVE_INET6 && NGX_HAVE_IPV6_RECVPKTINFO)
    struct in6_pktinfo    pkt6;
#endif
} ngx_addrinfo_t;

size_t ngx_set_srcaddr_cmsg(struct cmsghdr *cmsg,
    struct sockaddr *local_sockaddr);
ngx_int_t ngx_get_srcaddr_cmsg(struct cmsghdr *cmsg,
    struct sockaddr *local_sockaddr);

#endif

void ngx_event_recvmsg(ngx_event_t *ev);
ssize_t ngx_sendmsg(ngx_connection_t *c, struct msghdr *msg, int flags);
void ngx_udp_rbtree_insert_value(ngx_rbtree_node_t *temp,
    ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
#endif

void ngx_delete_udp_connection(void *data);


#endif /* _NGX_EVENT_UDP_H_INCLUDED_ */