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view src/event/ngx_event_udp.h @ 8867:5119c8150478

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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 ce6d9cf0f567
line wrap: on
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/*
 * 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_ */