Always include interface name for link-local addresses

2 files changed, 19 insertions, 3 deletions

diff --git a/src/printf.c b/src/printf.c
index d5f47ee..99c577b 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -28,6 +28,7 @@
 #include "peer.h"
 
 #include <arpa/inet.h>
+#include <net/if.h>
 
 
 static inline int snprintf_safe(char *buffer, size_t size, const char *format, ...) {
@@ -60,8 +61,15 @@ static int snprint_peer_address(const fastd_context_t *ctx, char *buffer, size_t
 	case AF_INET6:
 		if (!bind_address && ctx->conf->hide_ip_addresses)
 			return snprintf_safe(buffer, size, "[hidden]:%u", ntohs(address->in.sin_port));
-		if (inet_ntop(AF_INET6, &address->in6.sin6_addr, addr_buf, sizeof(addr_buf)))
-			return snprintf_safe(buffer, size, "[%s]:%u", addr_buf, ntohs(address->in6.sin6_port));
+		if (inet_ntop(AF_INET6, &address->in6.sin6_addr, addr_buf, sizeof(addr_buf))) {
+			if (IN6_IS_ADDR_LINKLOCAL(&address->in6.sin6_addr)) {
+				char ifname_buf[IF_NAMESIZE];
+				return snprintf_safe(buffer, size, "[%s%%%s]:%u", addr_buf, if_indextoname(address->in6.sin6_scope_id, ifname_buf), ntohs(address->in6.sin6_port));
+			}
+			else {
+				return snprintf_safe(buffer, size, "[%s]:%u", addr_buf, ntohs(address->in6.sin6_port));
+			}
+		}
 		else
 			return 0;
 
diff --git a/src/shell.c b/src/shell.c
index 80f925e..c1ecfa8 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -29,6 +29,7 @@
 #include "peer.h"
 
 #include <arpa/inet.h>
+#include <net/if.h>
 
 
 bool fastd_shell_exec(fastd_context_t *ctx, const char *command, const char *dir, const fastd_peer_t *peer, const fastd_peer_address_t *local_addr, const fastd_peer_address_t *peer_addr, int *ret) {
@@ -37,7 +38,8 @@ bool fastd_shell_exec(fastd_context_t *ctx, const char *command, const char *dir
 	char *cwd = get_current_dir_name();
 
 	if(!chdir(dir)) {
-		char buf[INET6_ADDRSTRLEN];
+		/* both INET6_ADDRSTRLEN and IFNAMESIZE already include space for the zero termination, so there is no need to add space for the '%' here. */
+		char buf[INET6_ADDRSTRLEN+IF_NAMESIZE];
 
 		snprintf(buf, sizeof(buf), "%u", (unsigned)getpid());
 		setenv("FASTD_PID", buf, 1);
@@ -64,6 +66,12 @@ bool fastd_shell_exec(fastd_context_t *ctx, const char *command, const char *dir
 
 		case AF_INET6:
 			inet_ntop(AF_INET6, &local_addr->in6.sin6_addr, buf, sizeof(buf));
+
+			if (IN6_IS_ADDR_LINKLOCAL(&local_addr->in6.sin6_addr)) {
+				if (if_indextoname(local_addr->in6.sin6_scope_id, buf+strlen(buf)+1))
+					buf[strlen(buf)] = '%';
+			}
+
 			setenv("LOCAL_ADDRESS", buf, 1);
 
 			snprintf(buf, sizeof(buf), "%u", ntohs(local_addr->in6.sin6_port));