feat: add variable connection_original_dst (#45)

Author: lingsamuel

patch/1.19.9/nginx-connection-original-dst.patch

@@ -0,0 +1,112 @@
+diff --git auto/os/linux auto/os/linux
+index 5e280eca..086e5372 100644
+--- auto/os/linux
++++ auto/os/linux
+@@ -190,6 +190,21 @@ ngx_feature_test="struct __user_cap_data_struct    data;
+                   (void) SYS_capset"
+ . auto/feature
+ 
++# netfilter_ipv4
++
++ngx_feature="netfilter_ipv4"
++ngx_feature_name="NGX_HAVE_NETFILTER_IPV4"
++ngx_feature_run=no
++ngx_feature_incs="#include <linux/netfilter_ipv4.h>"
++ngx_feature_path=
++ngx_feature_libs=
++ngx_feature_test="int so_original_dst;
++
++                  so_original_dst = SO_ORIGINAL_DST;
++
++                  (void) so_original_dst;"
++. auto/feature
++
+ 
+ # crypt_r()
+ 
+diff --git src/http/ngx_http_variables.c src/http/ngx_http_variables.c
+index c2113c84..1c2a06a7 100644
+--- src/http/ngx_http_variables.c
++++ src/http/ngx_http_variables.c
+@@ -130,6 +130,11 @@ static ngx_int_t ngx_http_variable_connection(ngx_http_request_t *r,
+ static ngx_int_t ngx_http_variable_connection_requests(ngx_http_request_t *r,
+     ngx_http_variable_value_t *v, uintptr_t data);
+ 
++#if (NGX_HAVE_NETFILTER_IPV4)
++static ngx_int_t ngx_http_variable_connection_dst(ngx_http_request_t *r,
++    ngx_http_variable_value_t *v, uintptr_t data);
++#endif
++
+ static ngx_int_t ngx_http_variable_nginx_version(ngx_http_request_t *r,
+     ngx_http_variable_value_t *v, uintptr_t data);
+ static ngx_int_t ngx_http_variable_hostname(ngx_http_request_t *r,
+@@ -342,6 +347,11 @@ static ngx_http_variable_t  ngx_http_core_variables[] = {
+     { ngx_string("connection_requests"), NULL,
+       ngx_http_variable_connection_requests, 0, 0, 0 },
+ 
++#if (NGX_HAVE_NETFILTER_IPV4)
++    { ngx_string("connection_original_dst"), NULL,
++      ngx_http_variable_connection_dst, 0, 0, 0 },
++#endif
++
+     { ngx_string("nginx_version"), NULL, ngx_http_variable_nginx_version,
+       0, 0, 0 },
+ 
+@@ -2252,6 +2262,43 @@ ngx_http_variable_connection_requests(ngx_http_request_t *r,
+ }
+ 
+ 
++#if (NGX_HAVE_NETFILTER_IPV4)
++static ngx_int_t
++ngx_http_variable_connection_dst(ngx_http_request_t *r,
++    ngx_http_variable_value_t *v, uintptr_t data)
++{
++    struct sockaddr_in  dst;
++    socklen_t           socklen;
++    int                 rn;
++    u_char             *p;
++
++    socklen = sizeof(struct sockaddr_in);
++
++    rn = getsockopt(r->connection->fd, SOL_IP, SO_ORIGINAL_DST, (void *) &dst,
++                    &socklen);
++    if (rn < 0) {
++        ngx_log_error(NGX_LOG_CRIT, r->connection->log, ngx_socket_errno,
++                      "getsockopt(SO_ORIGINAL_DST) failed");
++        return NGX_ERROR;
++    }
++
++    p = ngx_pnalloc(r->pool, NGX_SOCKADDR_STRLEN);
++    if (p == NULL) {
++        return NGX_ERROR;
++    }
++
++    v->len = ngx_sock_ntop((struct sockaddr *) &dst, socklen, p,
++                           NGX_SOCKADDR_STRLEN, dst.sin_port);
++    v->valid = 1;
++    v->no_cacheable = 0;
++    v->not_found = 0;
++    v->data = p;
++
++    return NGX_OK;
++}
++#endif
++
++
+ static ngx_int_t
+ ngx_http_variable_nginx_version(ngx_http_request_t *r,
+     ngx_http_variable_value_t *v, uintptr_t data)
+diff --git src/os/unix/ngx_linux_config.h src/os/unix/ngx_linux_config.h
+index 3036caeb..2353e9b3 100644
+--- src/os/unix/ngx_linux_config.h
++++ src/os/unix/ngx_linux_config.h
+@@ -103,6 +103,9 @@ typedef struct iocb  ngx_aiocb_t;
+ #include <linux/capability.h>
+ #endif
+ 
++#if (NGX_HAVE_NETFILTER_IPV4)
++#include <linux/netfilter_ipv4.h>
++#endif
+ 
+ #define NGX_LISTEN_BACKLOG        511
+