From 910166b3d67652abb54dece7e1cacdc9dcfdb659 Mon Sep 17 00:00:00 2001
From: Nikias Bassen
Date: Thu, 28 May 2020 04:06:28 +0200
Subject: iproxy: Allow specifying source address for the listening socket

---
 common/socket.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++---------
 common/socket.h |  2 +-
 2 files changed, 80 insertions(+), 16 deletions(-)

(limited to 'common')

diff --git a/common/socket.c b/common/socket.c
index a47de2a..1c38965 100644
--- a/common/socket.c
+++ b/common/socket.c
@@ -255,7 +255,7 @@ int socket_connect_unix(const char *filename)
 }
 #endif
 
-int socket_create(uint16_t port)
+int socket_create(const char* addr, uint16_t port)
 {
 	int sfd = -1;
 	int yes = 1;
@@ -269,9 +269,79 @@ int socket_create(uint16_t port)
 		wsa_init = 1;
 	}
 #endif
+	struct sockaddr* srcaddr;
+	int srcaddr_len = 0;
+	int domain = PF_INET;
+
+#if defined(AF_INET6)
+	struct sockaddr_in6 saddr6;
+	memset((void*) &saddr6, 0, sizeof(saddr6));
+	saddr6.sin6_family = AF_INET6;
+	saddr6.sin6_port = htons(port);
+	saddr6.sin6_addr = in6addr_loopback;
+#endif
+
 	struct sockaddr_in saddr;
+	memset((void*) &saddr, 0, sizeof(saddr));
+	saddr.sin_family = AF_INET;
+	saddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+	saddr.sin_port = htons(port);
+
+	if (addr) {
+		if (strchr(addr, ':')) {
+#ifdef AF_INET6
+#ifdef WIN32
+			struct sockaddr_storage ss;
+			int ss_size = sizeof(ss);
+			if (WSAStringToAddress((LPSTR)addr, AF_INET6, NULL, (struct sockaddr*)&ss, &ss_size) == 0) {
+				memcpy(&(saddr6.sin6_addr), &(((struct sockaddr_in6*)&ss)->sin6_addr), sizeof(struct in6_addr));
+			} else
+#else
+			if (inet_pton(AF_INET6, addr, &(saddr6.sin6_addr)) != 1)
+#endif
+			{
+				fprintf(stderr, "FATAL: Failed to convert '%s' to an IPv6 address.\n", addr);
+				socket_close(sfd);
+				return -1;
+			}
+			srcaddr = (struct sockaddr*)&saddr6;
+			srcaddr_len = sizeof(saddr6);
+			domain = PF_INET6;
+#else
+			fprintf(stderr, "FATAL: Got IPv6 address but AF_INET6 is not supported.\n");
+			socket_close(sfd);
+			return -1;
+#endif
+		} else {
+#ifdef WIN32
+			struct sockaddr_storage ss;
+			int ss_size = sizeof(ss);
+			if (WSAStringToAddress((LPSTR)addr, AF_INET, NULL, (struct sockaddr*)&ss, &ss_size) == 0) {
+				saddr.sin_addr.s_addr = ((struct sockaddr_in*)&ss)->sin_addr.s_addr;
+			} else
+#else
+			if (inet_pton(AF_INET, addr, &(saddr.sin_addr)) != 1)
+#endif
+			{
+				fprintf(stderr, "FATAL: Failed to convert '%s' to an IPv4 address.\n", addr);
+				socket_close(sfd);
+				return -1;
+			}
+			srcaddr = (struct sockaddr*)&saddr;
+			srcaddr_len = sizeof(saddr);
+		}
+	} else {
+#if !defined(WIN32) && defined(AF_INET6)
+		srcaddr = (struct sockaddr*)&saddr6;
+		srcaddr_len = sizeof(saddr6);
+		domain = PF_INET6;
+#else
+		srcaddr = (struct sockaddr*)&saddr;
+		srcaddr_len = sizeof(saddr);
+#endif
+	}
 
-	if (0 > (sfd = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP))) {
+	if ((sfd = socket(domain, SOCK_STREAM, IPPROTO_TCP)) < 0) {
 		perror("socket()");
 		return -1;
 	}
@@ -290,18 +360,13 @@ int socket_create(uint16_t port)
 	}
 #endif
 
-	memset((void *) &saddr, 0, sizeof(saddr));
-	saddr.sin_family = AF_INET;
-	saddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
-	saddr.sin_port = htons(port);
-
-	if (0 > bind(sfd, (struct sockaddr *) &saddr, sizeof(saddr))) {
+	if (bind(sfd, srcaddr, srcaddr_len) < 0) {
 		perror("bind()");
 		socket_close(sfd);
 		return -1;
 	}
 
-	if (listen(sfd, 1) == -1) {
+	if (listen(sfd, 1) < 0) {
 		perror("listen()");
 		socket_close(sfd);
 		return -1;
@@ -626,14 +691,13 @@ int socket_accept(int fd, uint16_t port)
 	socklen_t addr_len;
 #endif
 	int result;
+#ifdef AF_INET6
+	struct sockaddr_in6 addr;
+	addr_len = sizeof(addr);
+#else
 	struct sockaddr_in addr;
-
-	memset(&addr, 0, sizeof(addr));
-	addr.sin_family = AF_INET;
-	addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
-	addr.sin_port = htons(port);
-
 	addr_len = sizeof(addr);
+#endif
 	result = accept(fd, (struct sockaddr*)&addr, &addr_len);
 
 	return result;
diff --git a/common/socket.h b/common/socket.h
index 38eeddf..f510147 100644
--- a/common/socket.h
+++ b/common/socket.h
@@ -45,7 +45,7 @@ typedef enum fd_mode fd_mode;
 int socket_create_unix(const char *filename);
 int socket_connect_unix(const char *filename);
 #endif
-int socket_create(uint16_t port);
+int socket_create(const char *addr, uint16_t port);
 int socket_connect_addr(struct sockaddr *addr, uint16_t port);
 int socket_connect(const char *addr, uint16_t port);
 int socket_check_fd(int fd, fd_mode fdm, unsigned int timeout);
-- 
cgit v1.1-32-gdbae