e2ca8408c4 — curl

Subject

cf-socket: set scope_id for IPv6 link-local addresses

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Architecture & Compiler Flags

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

Build Log

(log yok)

Commit Diff GitHub →

lib/cf-socket.c +65 -3

lib/cf-socket.c+65 -3

@@ -44,6 +44,12 @@
	#include <arpa/inet.h>
	#endif

+	#ifdef HAVE_IFADDRS_H
+	#include <ifaddrs.h>
+	#endif
+	#ifdef HAVE_NET_IF_H
+	#include <net/if.h>
+	#endif
	#ifdef __VMS
	#include <in.h>
	#include <inet.h>
@@ -297,6 +303,49 @@ int Curl_sock_nosigpipe(curl_socket_t sockfd)
	}
	#endif /* USE_SO_NOSIGPIPE */

+	#if defined(USE_IPV6) && defined(HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID)
+	static uint32_t get_scope_id(struct Curl_easy *data,
+	struct sockaddr_in6 *sa6)
+	{
+	uint32_t scope_id = 0;
+	if(data->conn->scope_id)
+	return data->conn->scope_id;
+	/* NOLINTNEXTLINE(clang-analyzer-core.uninitialized.Assign) */
+	scope_id = sa6->sin6_scope_id;
+	if(!scope_id && IN6_IS_ADDR_LINKLOCAL(&sa6->sin6_addr)) {
+	/* The resolver did not set scope_id for this link-local address.
+	* Try to determine it from the system's network interfaces.
+	* Without a scope_id, connect() to a link-local address fails
+	* with EINVAL on Linux.
+	* NOTE: On multi-homed hosts with several interfaces having
+	* link-local addresses, this picks the first one found, which
+	* may not be the correct outgoing interface. */
+	#if defined(HAVE_GETIFADDRS) && defined(HAVE_NET_IF_H)
+	struct ifaddrs ifa, ifa_list;
+	if(getifaddrs(&ifa_list) == 0) {
+	for(ifa = ifa_list; ifa; ifa = ifa->ifa_next) {
+	if(ifa->ifa_addr && ifa->ifa_addr->sa_family == AF_INET6 &&
+	(ifa->ifa_flags & IFF_UP) &&
+	!(ifa->ifa_flags & IFF_LOOPBACK)) {
+	struct sockaddr_in6 s6 = (void )ifa->ifa_addr;
+	if(IN6_IS_ADDR_LINKLOCAL(&s6->sin6_addr) && s6->sin6_scope_id) {
+	scope_id = s6->sin6_scope_id;
+	infof(data,
+	"determined scope_id=%lu for link-local address "
+	"from local interface",
+	(unsigned long)scope_id);
+	break;
+	}
+	}
+	}
+	freeifaddrs(ifa_list);
+	}
+	#endif /* HAVE_GETIFADDRS && HAVE_NET_IF_H */
+	}
+	return scope_id;
+	}
+	#endif
+
	static CURLcode socket_open(struct Curl_easy *data,
	struct Curl_sockaddr_ex *addr,
	curl_socket_t *sockfd)
@@ -366,9 +415,9 @@ static CURLcode socket_open(struct Curl_easy *data,
	#endif

	#if defined(USE_IPV6) && defined(HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID)
-	if(data->conn->scope_id && (addr->family == AF_INET6)) {
+	if(addr->family == AF_INET6) {
	struct sockaddr_in6 * const sa6 = (void *)&addr->curl_sa_addr;
-	sa6->sin6_scope_id = data->conn->scope_id;
+	sa6->sin6_scope_id = get_scope_id(data, sa6);
	}
	#endif
	return CURLE_OK;
@@ -1085,7 +1134,20 @@ static CURLcode cf_socket_open(struct Curl_cfilter *cf,
	(void)setsockopt(ctx->sock, IPPROTO_IPV6, IPV6_V6ONLY,
	(void *)&on, sizeof(on));
	#endif
-	infof(data, " Trying [%s]:%d...", ctx->ip.remote_ip, ctx->ip.remote_port);
+	#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
+	{
+	struct sockaddr_in6 sa6 = (void )&ctx->addr.curl_sa_addr;
+	if(sa6->sin6_scope_id)
+	infof(data, " Trying [%s]:%d scope_id=%lu...",
+	ctx->ip.remote_ip, ctx->ip.remote_port,
+	(unsigned long)sa6->sin6_scope_id);
+	else
+	#endif
+	infof(data, " Trying [%s]:%d...",
+	ctx->ip.remote_ip, ctx->ip.remote_port);
+	#ifdef HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
+	}
+	#endif
	}
	else
	#endif