Mercurial > hg > nginx
view src/mail/ngx_mail_handler.c @ 8794:ba5977b38b2e quic
HTTP/3: reordered H3_MISSING_SETTINGS and H3_FRAME_UNEXPECTED.
The quic-http-34 is ambiguous as to what error should be generated for the
first frame in control stream:
Each side MUST initiate a single control stream at the beginning of
the connection and send its SETTINGS frame as the first frame on this
stream. If the first frame of the control stream is any other frame
type, this MUST be treated as a connection error of type
H3_MISSING_SETTINGS.
If a DATA frame is received on a control stream, the recipient MUST
respond with a connection error of type H3_FRAME_UNEXPECTED.
If a HEADERS frame is received on a control stream, the recipient MUST
respond with a connection error of type H3_FRAME_UNEXPECTED.
Previously, H3_FRAME_UNEXPECTED had priority, but now H3_MISSING_SETTINGS has.
The arguments in the spec sound more compelling for H3_MISSING_SETTINGS.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Fri, 11 Jun 2021 10:56:51 +0300 |
parents | ec1071830799 |
children | 0aaa09927703 |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #include <ngx_mail.h> static void ngx_mail_proxy_protocol_handler(ngx_event_t *rev); static void ngx_mail_init_session_handler(ngx_event_t *rev); static void ngx_mail_init_session(ngx_connection_t *c); #if (NGX_MAIL_SSL) static void ngx_mail_ssl_init_connection(ngx_ssl_t *ssl, ngx_connection_t *c); static void ngx_mail_ssl_handshake_handler(ngx_connection_t *c); static ngx_int_t ngx_mail_verify_cert(ngx_mail_session_t *s, ngx_connection_t *c); #endif void ngx_mail_init_connection(ngx_connection_t *c) { size_t len; ngx_uint_t i; ngx_event_t *rev; ngx_mail_port_t *port; struct sockaddr *sa; struct sockaddr_in *sin; ngx_mail_log_ctx_t *ctx; ngx_mail_in_addr_t *addr; ngx_mail_session_t *s; ngx_mail_addr_conf_t *addr_conf; ngx_mail_core_srv_conf_t *cscf; u_char text[NGX_SOCKADDR_STRLEN]; #if (NGX_HAVE_INET6) struct sockaddr_in6 *sin6; ngx_mail_in6_addr_t *addr6; #endif /* find the server configuration for the address:port */ port = c->listening->servers; if (port->naddrs > 1) { /* * There are several addresses on this port and one of them * is the "*:port" wildcard so getsockname() is needed to determine * the server address. * * AcceptEx() already gave this address. */ if (ngx_connection_local_sockaddr(c, NULL, 0) != NGX_OK) { ngx_mail_close_connection(c); return; } sa = c->local_sockaddr; switch (sa->sa_family) { #if (NGX_HAVE_INET6) case AF_INET6: sin6 = (struct sockaddr_in6 *) sa; addr6 = port->addrs; /* the last address is "*" */ for (i = 0; i < port->naddrs - 1; i++) { if (ngx_memcmp(&addr6[i].addr6, &sin6->sin6_addr, 16) == 0) { break; } } addr_conf = &addr6[i].conf; break; #endif default: /* AF_INET */ sin = (struct sockaddr_in *) sa; addr = port->addrs; /* the last address is "*" */ for (i = 0; i < port->naddrs - 1; i++) { if (addr[i].addr == sin->sin_addr.s_addr) { break; } } addr_conf = &addr[i].conf; break; } } else { switch (c->local_sockaddr->sa_family) { #if (NGX_HAVE_INET6) case AF_INET6: addr6 = port->addrs; addr_conf = &addr6[0].conf; break; #endif default: /* AF_INET */ addr = port->addrs; addr_conf = &addr[0].conf; break; } } s = ngx_pcalloc(c->pool, sizeof(ngx_mail_session_t)); if (s == NULL) { ngx_mail_close_connection(c); return; } s->signature = NGX_MAIL_MODULE; s->main_conf = addr_conf->ctx->main_conf; s->srv_conf = addr_conf->ctx->srv_conf; #if (NGX_MAIL_SSL) s->ssl = addr_conf->ssl; #endif s->addr_text = &addr_conf->addr_text; c->data = s; s->connection = c; cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); ngx_set_connection_log(c, cscf->error_log); len = ngx_sock_ntop(c->sockaddr, c->socklen, text, NGX_SOCKADDR_STRLEN, 1); ngx_log_error(NGX_LOG_INFO, c->log, 0, "*%uA client %*s connected to %V", c->number, len, text, s->addr_text); ctx = ngx_palloc(c->pool, sizeof(ngx_mail_log_ctx_t)); if (ctx == NULL) { ngx_mail_close_connection(c); return; } ctx->client = &c->addr_text; ctx->session = s; c->log->connection = c->number; c->log->handler = ngx_mail_log_error; c->log->data = ctx; c->log->action = "sending client greeting line"; c->log_error = NGX_ERROR_INFO; rev = c->read; rev->handler = ngx_mail_init_session_handler; if (addr_conf->proxy_protocol) { c->log->action = "reading PROXY protocol"; rev->handler = ngx_mail_proxy_protocol_handler; if (!rev->ready) { ngx_add_timer(rev, cscf->timeout); if (ngx_handle_read_event(rev, 0) != NGX_OK) { ngx_mail_close_connection(c); } return; } } if (ngx_use_accept_mutex) { ngx_post_event(rev, &ngx_posted_events); return; } rev->handler(rev); } static void ngx_mail_proxy_protocol_handler(ngx_event_t *rev) { u_char *p, buf[NGX_PROXY_PROTOCOL_MAX_HEADER]; size_t size; ssize_t n; ngx_err_t err; ngx_connection_t *c; ngx_mail_session_t *s; ngx_mail_core_srv_conf_t *cscf; c = rev->data; s = c->data; ngx_log_debug0(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail PROXY protocol handler"); if (rev->timedout) { ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out"); c->timedout = 1; ngx_mail_close_connection(c); return; } n = recv(c->fd, (char *) buf, sizeof(buf), MSG_PEEK); err = ngx_socket_errno; ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "recv(): %z", n); if (n == -1) { if (err == NGX_EAGAIN) { rev->ready = 0; if (!rev->timer_set) { cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); ngx_add_timer(rev, cscf->timeout); } if (ngx_handle_read_event(rev, 0) != NGX_OK) { ngx_mail_close_connection(c); } return; } ngx_connection_error(c, err, "recv() failed"); ngx_mail_close_connection(c); return; } p = ngx_proxy_protocol_read(c, buf, buf + n); if (p == NULL) { ngx_mail_close_connection(c); return; } size = p - buf; if (c->recv(c, buf, size) != (ssize_t) size) { ngx_mail_close_connection(c); return; } if (ngx_mail_realip_handler(s) != NGX_OK) { ngx_mail_close_connection(c); return; } ngx_mail_init_session_handler(rev); } static void ngx_mail_init_session_handler(ngx_event_t *rev) { ngx_connection_t *c; c = rev->data; #if (NGX_MAIL_SSL) { ngx_mail_session_t *s; ngx_mail_ssl_conf_t *sslcf; s = c->data; sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module); if (sslcf->enable || s->ssl) { c->log->action = "SSL handshaking"; ngx_mail_ssl_init_connection(&sslcf->ssl, c); return; } } #endif ngx_mail_init_session(c); } #if (NGX_MAIL_SSL) void ngx_mail_starttls_handler(ngx_event_t *rev) { ngx_connection_t *c; ngx_mail_session_t *s; ngx_mail_ssl_conf_t *sslcf; c = rev->data; s = c->data; s->starttls = 1; c->log->action = "in starttls state"; sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module); ngx_mail_ssl_init_connection(&sslcf->ssl, c); } static void ngx_mail_ssl_init_connection(ngx_ssl_t *ssl, ngx_connection_t *c) { ngx_mail_session_t *s; ngx_mail_core_srv_conf_t *cscf; if (ngx_ssl_create_connection(ssl, c, 0) != NGX_OK) { ngx_mail_close_connection(c); return; } if (ngx_ssl_handshake(c) == NGX_AGAIN) { s = c->data; if (!c->read->timer_set) { cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); ngx_add_timer(c->read, cscf->timeout); } c->ssl->handler = ngx_mail_ssl_handshake_handler; return; } ngx_mail_ssl_handshake_handler(c); } static void ngx_mail_ssl_handshake_handler(ngx_connection_t *c) { ngx_mail_session_t *s; ngx_mail_core_srv_conf_t *cscf; if (c->ssl->handshaked) { s = c->data; if (ngx_mail_verify_cert(s, c) != NGX_OK) { return; } if (s->starttls) { cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); c->read->handler = cscf->protocol->init_protocol; c->write->handler = ngx_mail_send; cscf->protocol->init_protocol(c->read); return; } c->read->ready = 0; ngx_mail_init_session(c); return; } ngx_mail_close_connection(c); } static ngx_int_t ngx_mail_verify_cert(ngx_mail_session_t *s, ngx_connection_t *c) { long rc; X509 *cert; ngx_mail_ssl_conf_t *sslcf; ngx_mail_core_srv_conf_t *cscf; sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module); if (!sslcf->verify) { return NGX_OK; } rc = SSL_get_verify_result(c->ssl->connection); if (rc != X509_V_OK && (sslcf->verify != 3 || !ngx_ssl_verify_error_optional(rc))) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "client SSL certificate verify error: (%l:%s)", rc, X509_verify_cert_error_string(rc)); ngx_ssl_remove_cached_session(c->ssl->session_ctx, (SSL_get0_session(c->ssl->connection))); cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); s->out = cscf->protocol->cert_error; s->quit = 1; c->write->handler = ngx_mail_send; ngx_mail_send(s->connection->write); return NGX_ERROR; } if (sslcf->verify == 1) { cert = SSL_get_peer_certificate(c->ssl->connection); if (cert == NULL) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "client sent no required SSL certificate"); ngx_ssl_remove_cached_session(c->ssl->session_ctx, (SSL_get0_session(c->ssl->connection))); cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); s->out = cscf->protocol->no_cert; s->quit = 1; c->write->handler = ngx_mail_send; ngx_mail_send(s->connection->write); return NGX_ERROR; } X509_free(cert); } return NGX_OK; } #endif static void ngx_mail_init_session(ngx_connection_t *c) { ngx_mail_session_t *s; ngx_mail_core_srv_conf_t *cscf; s = c->data; c->log->action = "sending client greeting line"; cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); s->protocol = cscf->protocol->type; s->ctx = ngx_pcalloc(c->pool, sizeof(void *) * ngx_mail_max_module); if (s->ctx == NULL) { ngx_mail_session_internal_server_error(s); return; } c->write->handler = ngx_mail_send; cscf->protocol->init_session(s, c); } ngx_int_t ngx_mail_salt(ngx_mail_session_t *s, ngx_connection_t *c, ngx_mail_core_srv_conf_t *cscf) { s->salt.data = ngx_pnalloc(c->pool, sizeof(" <18446744073709551616.@>" CRLF) - 1 + NGX_TIME_T_LEN + cscf->server_name.len); if (s->salt.data == NULL) { return NGX_ERROR; } s->salt.len = ngx_sprintf(s->salt.data, "<%ul.%T@%V>" CRLF, ngx_random(), ngx_time(), &cscf->server_name) - s->salt.data; return NGX_OK; } #if (NGX_MAIL_SSL) ngx_int_t ngx_mail_starttls_only(ngx_mail_session_t *s, ngx_connection_t *c) { ngx_mail_ssl_conf_t *sslcf; if (c->ssl) { return 0; } sslcf = ngx_mail_get_module_srv_conf(s, ngx_mail_ssl_module); if (sslcf->starttls == NGX_MAIL_STARTTLS_ONLY) { return 1; } return 0; } #endif ngx_int_t ngx_mail_auth_plain(ngx_mail_session_t *s, ngx_connection_t *c, ngx_uint_t n) { u_char *p, *last; ngx_str_t *arg, plain; arg = s->args.elts; #if (NGX_DEBUG_MAIL_PASSWD) ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail auth plain: \"%V\"", &arg[n]); #endif plain.data = ngx_pnalloc(c->pool, ngx_base64_decoded_length(arg[n].len)); if (plain.data == NULL) { return NGX_ERROR; } if (ngx_decode_base64(&plain, &arg[n]) != NGX_OK) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "client sent invalid base64 encoding in AUTH PLAIN command"); return NGX_MAIL_PARSE_INVALID_COMMAND; } p = plain.data; last = p + plain.len; while (p < last && *p++) { /* void */ } if (p == last) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "client sent invalid login in AUTH PLAIN command"); return NGX_MAIL_PARSE_INVALID_COMMAND; } s->login.data = p; while (p < last && *p) { p++; } if (p == last) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "client sent invalid password in AUTH PLAIN command"); return NGX_MAIL_PARSE_INVALID_COMMAND; } s->login.len = p++ - s->login.data; s->passwd.len = last - p; s->passwd.data = p; #if (NGX_DEBUG_MAIL_PASSWD) ngx_log_debug2(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail auth plain: \"%V\" \"%V\"", &s->login, &s->passwd); #endif return NGX_DONE; } ngx_int_t ngx_mail_auth_login_username(ngx_mail_session_t *s, ngx_connection_t *c, ngx_uint_t n) { ngx_str_t *arg; arg = s->args.elts; ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail auth login username: \"%V\"", &arg[n]); s->login.data = ngx_pnalloc(c->pool, ngx_base64_decoded_length(arg[n].len)); if (s->login.data == NULL) { return NGX_ERROR; } if (ngx_decode_base64(&s->login, &arg[n]) != NGX_OK) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "client sent invalid base64 encoding in AUTH LOGIN command"); return NGX_MAIL_PARSE_INVALID_COMMAND; } ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail auth login username: \"%V\"", &s->login); return NGX_OK; } ngx_int_t ngx_mail_auth_login_password(ngx_mail_session_t *s, ngx_connection_t *c) { ngx_str_t *arg; arg = s->args.elts; #if (NGX_DEBUG_MAIL_PASSWD) ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail auth login password: \"%V\"", &arg[0]); #endif s->passwd.data = ngx_pnalloc(c->pool, ngx_base64_decoded_length(arg[0].len)); if (s->passwd.data == NULL) { return NGX_ERROR; } if (ngx_decode_base64(&s->passwd, &arg[0]) != NGX_OK) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "client sent invalid base64 encoding in AUTH LOGIN command"); return NGX_MAIL_PARSE_INVALID_COMMAND; } #if (NGX_DEBUG_MAIL_PASSWD) ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail auth login password: \"%V\"", &s->passwd); #endif return NGX_DONE; } ngx_int_t ngx_mail_auth_cram_md5_salt(ngx_mail_session_t *s, ngx_connection_t *c, char *prefix, size_t len) { u_char *p; ngx_str_t salt; ngx_uint_t n; p = ngx_pnalloc(c->pool, len + ngx_base64_encoded_length(s->salt.len) + 2); if (p == NULL) { return NGX_ERROR; } salt.data = ngx_cpymem(p, prefix, len); s->salt.len -= 2; ngx_encode_base64(&salt, &s->salt); s->salt.len += 2; n = len + salt.len; p[n++] = CR; p[n++] = LF; s->out.len = n; s->out.data = p; return NGX_OK; } ngx_int_t ngx_mail_auth_cram_md5(ngx_mail_session_t *s, ngx_connection_t *c) { u_char *p, *last; ngx_str_t *arg; arg = s->args.elts; ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail auth cram-md5: \"%V\"", &arg[0]); s->login.data = ngx_pnalloc(c->pool, ngx_base64_decoded_length(arg[0].len)); if (s->login.data == NULL) { return NGX_ERROR; } if (ngx_decode_base64(&s->login, &arg[0]) != NGX_OK) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "client sent invalid base64 encoding in AUTH CRAM-MD5 command"); return NGX_MAIL_PARSE_INVALID_COMMAND; } p = s->login.data; last = p + s->login.len; while (p < last) { if (*p++ == ' ') { s->login.len = p - s->login.data - 1; s->passwd.len = last - p; s->passwd.data = p; break; } } if (s->passwd.len != 32) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "client sent invalid CRAM-MD5 hash in AUTH CRAM-MD5 command"); return NGX_MAIL_PARSE_INVALID_COMMAND; } ngx_log_debug2(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail auth cram-md5: \"%V\" \"%V\"", &s->login, &s->passwd); s->auth_method = NGX_MAIL_AUTH_CRAM_MD5; return NGX_DONE; } ngx_int_t ngx_mail_auth_external(ngx_mail_session_t *s, ngx_connection_t *c, ngx_uint_t n) { ngx_str_t *arg, external; arg = s->args.elts; ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail auth external: \"%V\"", &arg[n]); external.data = ngx_pnalloc(c->pool, ngx_base64_decoded_length(arg[n].len)); if (external.data == NULL) { return NGX_ERROR; } if (ngx_decode_base64(&external, &arg[n]) != NGX_OK) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "client sent invalid base64 encoding in AUTH EXTERNAL command"); return NGX_MAIL_PARSE_INVALID_COMMAND; } s->login.len = external.len; s->login.data = external.data; ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "mail auth external: \"%V\"", &s->login); s->auth_method = NGX_MAIL_AUTH_EXTERNAL; return NGX_DONE; } void ngx_mail_send(ngx_event_t *wev) { ngx_int_t n; ngx_connection_t *c; ngx_mail_session_t *s; ngx_mail_core_srv_conf_t *cscf; c = wev->data; s = c->data; if (wev->timedout) { ngx_log_error(NGX_LOG_INFO, c->log, NGX_ETIMEDOUT, "client timed out"); c->timedout = 1; ngx_mail_close_connection(c); return; } if (s->out.len == 0) { if (ngx_handle_write_event(c->write, 0) != NGX_OK) { ngx_mail_close_connection(c); } return; } n = c->send(c, s->out.data, s->out.len); if (n > 0) { s->out.data += n; s->out.len -= n; if (s->out.len != 0) { goto again; } if (wev->timer_set) { ngx_del_timer(wev); } if (s->quit) { ngx_mail_close_connection(c); return; } if (s->blocked) { c->read->handler(c->read); } return; } if (n == NGX_ERROR) { ngx_mail_close_connection(c); return; } /* n == NGX_AGAIN */ again: cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); ngx_add_timer(c->write, cscf->timeout); if (ngx_handle_write_event(c->write, 0) != NGX_OK) { ngx_mail_close_connection(c); return; } } ngx_int_t ngx_mail_read_command(ngx_mail_session_t *s, ngx_connection_t *c) { ssize_t n; ngx_int_t rc; ngx_str_t l; ngx_mail_core_srv_conf_t *cscf; if (s->buffer->last < s->buffer->end) { n = c->recv(c, s->buffer->last, s->buffer->end - s->buffer->last); if (n == NGX_ERROR || n == 0) { ngx_mail_close_connection(c); return NGX_ERROR; } if (n > 0) { s->buffer->last += n; } if (n == NGX_AGAIN) { if (s->buffer->pos == s->buffer->last) { return NGX_AGAIN; } } } cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); rc = cscf->protocol->parse_command(s); if (rc == NGX_AGAIN) { if (s->buffer->last < s->buffer->end) { return rc; } l.len = s->buffer->last - s->buffer->start; l.data = s->buffer->start; ngx_log_error(NGX_LOG_INFO, c->log, 0, "client sent too long command \"%V\"", &l); s->quit = 1; return NGX_MAIL_PARSE_INVALID_COMMAND; } if (rc == NGX_MAIL_PARSE_INVALID_COMMAND) { s->errors++; if (s->errors >= cscf->max_errors) { ngx_log_error(NGX_LOG_INFO, c->log, 0, "client sent too many invalid commands"); s->quit = 1; } return rc; } if (rc == NGX_IMAP_NEXT) { return rc; } if (rc == NGX_ERROR) { ngx_mail_close_connection(c); return NGX_ERROR; } return NGX_OK; } void ngx_mail_auth(ngx_mail_session_t *s, ngx_connection_t *c) { s->args.nelts = 0; if (s->buffer->pos == s->buffer->last) { s->buffer->pos = s->buffer->start; s->buffer->last = s->buffer->start; } s->state = 0; if (c->read->timer_set) { ngx_del_timer(c->read); } s->login_attempt++; ngx_mail_auth_http_init(s); } void ngx_mail_session_internal_server_error(ngx_mail_session_t *s) { ngx_mail_core_srv_conf_t *cscf; cscf = ngx_mail_get_module_srv_conf(s, ngx_mail_core_module); s->out = cscf->protocol->internal_server_error; s->quit = 1; ngx_mail_send(s->connection->write); } void ngx_mail_close_connection(ngx_connection_t *c) { ngx_pool_t *pool; ngx_log_debug1(NGX_LOG_DEBUG_MAIL, c->log, 0, "close mail connection: %d", c->fd); #if (NGX_MAIL_SSL) if (c->ssl) { if (ngx_ssl_shutdown(c) == NGX_AGAIN) { c->ssl->handler = ngx_mail_close_connection; return; } } #endif #if (NGX_STAT_STUB) (void) ngx_atomic_fetch_add(ngx_stat_active, -1); #endif c->destroyed = 1; pool = c->pool; ngx_close_connection(c); ngx_destroy_pool(pool); } u_char * ngx_mail_log_error(ngx_log_t *log, u_char *buf, size_t len) { u_char *p; ngx_mail_session_t *s; ngx_mail_log_ctx_t *ctx; if (log->action) { p = ngx_snprintf(buf, len, " while %s", log->action); len -= p - buf; buf = p; } ctx = log->data; p = ngx_snprintf(buf, len, ", client: %V", ctx->client); len -= p - buf; buf = p; s = ctx->session; if (s == NULL) { return p; } p = ngx_snprintf(buf, len, "%s, server: %V", s->starttls ? " using starttls" : "", s->addr_text); len -= p - buf; buf = p; if (s->login.len == 0) { return p; } p = ngx_snprintf(buf, len, ", login: \"%V\"", &s->login); len -= p - buf; buf = p; if (s->proxy == NULL) { return p; } p = ngx_snprintf(buf, len, ", upstream: %V", s->proxy->upstream.name); return p; }