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view src/event/ngx_event_udp.h @ 8045:aa28c802409f

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Resolver: make TCP write timer event cancelable. Similar to 70e65bf8dfd7, the change is made to ensure that the ability to cancel resolver tasks is fully controlled by the caller. As mentioned in the referenced commit, it is safe to make this timer cancelable because resolve tasks can have their own timeouts that are not cancelable. The scenario where this may become a problem is a periodic background resolve task (not tied to a specific request or a client connection), which receives a response with short TTL, large enough to warrant fallback to a TCP query. With each event loop wakeup, we either have a previously set write timer instance or schedule a new one. The non-cancelable write timer can delay or block graceful shutdown of a worker even if the ngx_resolver_ctx_t->cancelable flag is set by the API user, and there are no other tasks or connections. We use the resolver API in this way to maintain the list of upstream server addresses specified with the 'resolve' parameter, and there could be third-party modules implementing similar logic.
author Aleksei Bavshin <a.bavshin@f5.com>
date Wed, 01 Jun 2022 20:17:23 -0700
parents 0f6cc8f73744
children ce6d9cf0f567
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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_ */