selftests/bpf: Support af_unix SOCK_DGRAM socket pair creation

Handle af_unix in init_addr_loopback(). For pair creation, bind() the peer
socket to make SOCK_DGRAM connect() happy.

Signed-off-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20250515-selftests-sockmap-redir-v3-1-a1ea723f7e7e@rbox.co

diff --git a/tools/testing/selftests/bpf/prog_tests/socket_helpers.h b/tools/testing/selftests/bpf/prog_tests/socket_helpers.h
index 1bdfb79..e505c2f 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/socket_helpers.h
+++ b/tools/testing/selftests/bpf/prog_tests/socket_helpers.h
@@ -3,6 +3,7 @@
 #ifndef __SOCKET_HELPERS__
 #define __SOCKET_HELPERS__
 
+#include <sys/un.h>
 #include <linux/vm_sockets.h>
 
 /* include/linux/net.h */
@@ -169,6 +170,15 @@ static inline void init_addr_loopback6(struct sockaddr_storage *ss,
        *len = sizeof(*addr6);
 }
 
+static inline void init_addr_loopback_unix(struct sockaddr_storage *ss,
+                                          socklen_t *len)
+{
+       struct sockaddr_un *addr = memset(ss, 0, sizeof(*ss));
+
+       addr->sun_family = AF_UNIX;
+       *len = sizeof(sa_family_t);
+}
+
 static inline void init_addr_loopback_vsock(struct sockaddr_storage *ss,
                                            socklen_t *len)
 {
@@ -190,6 +200,9 @@ static inline void init_addr_loopback(int family, struct sockaddr_storage *ss,
        case AF_INET6:
                init_addr_loopback6(ss, len);
                return;
+       case AF_UNIX:
+               init_addr_loopback_unix(ss, len);
+               return;
        case AF_VSOCK:
                init_addr_loopback_vsock(ss, len);
                return;
@@ -315,21 +328,27 @@ static inline int create_pair(int family, int sotype, int *p0, int *p1)
 {
        __close_fd int s, c = -1, p = -1;
        struct sockaddr_storage addr;
-       socklen_t len = sizeof(addr);
+       socklen_t len;
        int err;
 
        s = socket_loopback(family, sotype);
        if (s < 0)
                return s;
 
-       err = xgetsockname(s, sockaddr(&addr), &len);
-       if (err)
-               return err;
-
        c = xsocket(family, sotype, 0);
        if (c < 0)
                return c;
 
+       init_addr_loopback(family, &addr, &len);
+       err = xbind(c, sockaddr(&addr), len);
+       if (err)
+               return err;
+
+       len = sizeof(addr);
+       err = xgetsockname(s, sockaddr(&addr), &len);
+       if (err)
+               return err;
+
        err = connect(c, sockaddr(&addr), len);
        if (err) {
                if (errno != EINPROGRESS) {