Mail: realip module.

When configured with the "set_real_ip_from", it can set client's IP
address as visible in logs to the one obtained via the PROXY protocol.

auto/modules

@@ -985,6 +985,12 @@ if [ $MAIL != NO ]; then
     ngx_module_srcs=src/mail/ngx_mail_proxy_module.c
 
     . auto/module
+
+    ngx_module_name=ngx_mail_realip_module
+    ngx_module_deps=
+    ngx_module_srcs=src/mail/ngx_mail_realip_module.c
+
+    . auto/module
 fi
 
 

src/mail/ngx_mail.h

@@ -408,6 +408,7 @@ char *ngx_mail_capabilities(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
 /* STUB */
 void ngx_mail_proxy_init(ngx_mail_session_t *s, ngx_addr_t *peer);
 void ngx_mail_auth_http_init(ngx_mail_session_t *s);
+ngx_int_t ngx_mail_realip_handler(ngx_mail_session_t *s);
 /**/
 
 

src/mail/ngx_mail_handler.c

@@ -260,6 +260,11 @@ ngx_mail_proxy_protocol_handler(ngx_event_t *rev)
         return;
     }
 
+    if (ngx_mail_realip_handler(s) != NGX_OK) {
+        ngx_mail_close_connection(c);
+        return;
+    }
+
     ngx_mail_init_session_handler(rev);
 }
 

src/mail/ngx_mail_realip_module.c

@@ -0,0 +1,269 @@
+
+/*
+ * Copyright (C) Igor Sysoev
+ * Copyright (C) Nginx, Inc.
+ */
+
+
+#include <ngx_config.h>
+#include <ngx_core.h>
+#include <ngx_mail.h>
+
+
+typedef struct {
+    ngx_array_t       *from;     /* array of ngx_cidr_t */
+} ngx_mail_realip_srv_conf_t;
+
+
+static ngx_int_t ngx_mail_realip_set_addr(ngx_mail_session_t *s,
+    ngx_addr_t *addr);
+static char *ngx_mail_realip_from(ngx_conf_t *cf, ngx_command_t *cmd,
+    void *conf);
+static void *ngx_mail_realip_create_srv_conf(ngx_conf_t *cf);
+static char *ngx_mail_realip_merge_srv_conf(ngx_conf_t *cf, void *parent,
+    void *child);
+
+
+static ngx_command_t  ngx_mail_realip_commands[] = {
+
+    { ngx_string("set_real_ip_from"),
+      NGX_MAIL_MAIN_CONF|NGX_MAIL_SRV_CONF|NGX_CONF_TAKE1,
+      ngx_mail_realip_from,
+      NGX_MAIL_SRV_CONF_OFFSET,
+      0,
+      NULL },
+
+      ngx_null_command
+};
+
+
+static ngx_mail_module_t  ngx_mail_realip_module_ctx = {
+    NULL,                                  /* protocol */
+
+    NULL,                                  /* create main configuration */
+    NULL,                                  /* init main configuration */
+
+    ngx_mail_realip_create_srv_conf,       /* create server configuration */
+    ngx_mail_realip_merge_srv_conf         /* merge server configuration */
+};
+
+
+ngx_module_t  ngx_mail_realip_module = {
+    NGX_MODULE_V1,
+    &ngx_mail_realip_module_ctx,           /* module context */
+    ngx_mail_realip_commands,              /* module directives */
+    NGX_MAIL_MODULE,                       /* module type */
+    NULL,                                  /* init master */
+    NULL,                                  /* init module */
+    NULL,                                  /* init process */
+    NULL,                                  /* init thread */
+    NULL,                                  /* exit thread */
+    NULL,                                  /* exit process */
+    NULL,                                  /* exit master */
+    NGX_MODULE_V1_PADDING
+};
+
+
+ngx_int_t
+ngx_mail_realip_handler(ngx_mail_session_t *s)
+{
+    ngx_addr_t                   addr;
+    ngx_connection_t            *c;
+    ngx_mail_realip_srv_conf_t  *rscf;
+
+    rscf = ngx_mail_get_module_srv_conf(s, ngx_mail_realip_module);
+
+    if (rscf->from == NULL) {
+        return NGX_OK;
+    }
+
+    c = s->connection;
+
+    if (c->proxy_protocol == NULL) {
+        return NGX_OK;
+    }
+
+    if (ngx_cidr_match(c->sockaddr, rscf->from) != NGX_OK) {
+        return NGX_OK;
+    }
+
+    if (ngx_parse_addr(c->pool, &addr, c->proxy_protocol->src_addr.data,
+                       c->proxy_protocol->src_addr.len)
+        != NGX_OK)
+    {
+        return NGX_OK;
+    }
+
+    ngx_inet_set_port(addr.sockaddr, c->proxy_protocol->src_port);
+
+    return ngx_mail_realip_set_addr(s, &addr);
+}
+
+
+static ngx_int_t
+ngx_mail_realip_set_addr(ngx_mail_session_t *s, ngx_addr_t *addr)
+{
+    size_t             len;
+    u_char            *p;
+    u_char             text[NGX_SOCKADDR_STRLEN];
+    ngx_connection_t  *c;
+
+    c = s->connection;
+
+    len = ngx_sock_ntop(addr->sockaddr, addr->socklen, text,
+                        NGX_SOCKADDR_STRLEN, 0);
+    if (len == 0) {
+        return NGX_ERROR;
+    }
+
+    p = ngx_pnalloc(c->pool, len);
+    if (p == NULL) {
+        return NGX_ERROR;
+    }
+
+    ngx_memcpy(p, text, len);
+
+    c->sockaddr = addr->sockaddr;
+    c->socklen = addr->socklen;
+    c->addr_text.len = len;
+    c->addr_text.data = p;
+
+    return NGX_OK;
+}
+
+
+static char *
+ngx_mail_realip_from(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
+{
+    ngx_mail_realip_srv_conf_t *rscf = conf;
+
+    ngx_int_t             rc;
+    ngx_str_t            *value;
+    ngx_url_t             u;
+    ngx_cidr_t            c, *cidr;
+    ngx_uint_t            i;
+    struct sockaddr_in   *sin;
+#if (NGX_HAVE_INET6)
+    struct sockaddr_in6  *sin6;
+#endif
+
+    value = cf->args->elts;
+
+    if (rscf->from == NULL) {
+        rscf->from = ngx_array_create(cf->pool, 2,
+                                      sizeof(ngx_cidr_t));
+        if (rscf->from == NULL) {
+            return NGX_CONF_ERROR;
+        }
+    }
+
+#if (NGX_HAVE_UNIX_DOMAIN)
+
+    if (ngx_strcmp(value[1].data, "unix:") == 0) {
+        cidr = ngx_array_push(rscf->from);
+        if (cidr == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        cidr->family = AF_UNIX;
+        return NGX_CONF_OK;
+    }
+
+#endif
+
+    rc = ngx_ptocidr(&value[1], &c);
+
+    if (rc != NGX_ERROR) {
+        if (rc == NGX_DONE) {
+            ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
+                               "low address bits of %V are meaningless",
+                               &value[1]);
+        }
+
+        cidr = ngx_array_push(rscf->from);
+        if (cidr == NULL) {
+            return NGX_CONF_ERROR;
+        }
+
+        *cidr = c;
+
+        return NGX_CONF_OK;
+    }
+
+    ngx_memzero(&u, sizeof(ngx_url_t));
+    u.host = value[1];
+
+    if (ngx_inet_resolve_host(cf->pool, &u) != NGX_OK) {
+        if (u.err) {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                               "%s in set_real_ip_from \"%V\"",
+                               u.err, &u.host);
+        }
+
+        return NGX_CONF_ERROR;
+    }
+
+    cidr = ngx_array_push_n(rscf->from, u.naddrs);
+    if (cidr == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    ngx_memzero(cidr, u.naddrs * sizeof(ngx_cidr_t));
+
+    for (i = 0; i < u.naddrs; i++) {
+        cidr[i].family = u.addrs[i].sockaddr->sa_family;
+
+        switch (cidr[i].family) {
+
+#if (NGX_HAVE_INET6)
+        case AF_INET6:
+            sin6 = (struct sockaddr_in6 *) u.addrs[i].sockaddr;
+            cidr[i].u.in6.addr = sin6->sin6_addr;
+            ngx_memset(cidr[i].u.in6.mask.s6_addr, 0xff, 16);
+            break;
+#endif
+
+        default: /* AF_INET */
+            sin = (struct sockaddr_in *) u.addrs[i].sockaddr;
+            cidr[i].u.in.addr = sin->sin_addr.s_addr;
+            cidr[i].u.in.mask = 0xffffffff;
+            break;
+        }
+    }
+
+    return NGX_CONF_OK;
+}
+
+
+static void *
+ngx_mail_realip_create_srv_conf(ngx_conf_t *cf)
+{
+    ngx_mail_realip_srv_conf_t  *conf;
+
+    conf = ngx_pcalloc(cf->pool, sizeof(ngx_mail_realip_srv_conf_t));
+    if (conf == NULL) {
+        return NULL;
+    }
+
+    /*
+     * set by ngx_pcalloc():
+     *
+     *     conf->from = NULL;
+     */
+
+    return conf;
+}
+
+
+static char *
+ngx_mail_realip_merge_srv_conf(ngx_conf_t *cf, void *parent, void *child)
+{
+    ngx_mail_realip_srv_conf_t *prev = parent;
+    ngx_mail_realip_srv_conf_t *conf = child;
+
+    if (conf->from == NULL) {
+        conf->from = prev->from;
+    }
+
+    return NGX_CONF_OK;
+}