bpf, sockmap: Build helper to create connected socket pair

A common operation for testing is to spin up a pair of sockets that are
connected. Then we can use these to run specific tests that need to
send data, check BPF programs and so on.

The sockmap_listen programs already have this logic lets move it into
the new sockmap_helpers header file for general use.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20230523025618.113937-11-john.fastabend@gmail.com

diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h b/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
index 5aa99e6..d126654 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_helpers.h
@@ -269,4 +269,122 @@ static inline struct sockaddr *sockaddr(struct sockaddr_storage *ss)
        return (struct sockaddr *)ss;
 }
 
+static inline int add_to_sockmap(int sock_mapfd, int fd1, int fd2)
+{
+       u64 value;
+       u32 key;
+       int err;
+
+       key = 0;
+       value = fd1;
+       err = xbpf_map_update_elem(sock_mapfd, &key, &value, BPF_NOEXIST);
+       if (err)
+               return err;
+
+       key = 1;
+       value = fd2;
+       return xbpf_map_update_elem(sock_mapfd, &key, &value, BPF_NOEXIST);
+}
+
+static inline int create_pair(int s, int family, int sotype, int *c, int *p)
+{
+       struct sockaddr_storage addr;
+       socklen_t len;
+       int err = 0;
+
+       len = sizeof(addr);
+       err = xgetsockname(s, sockaddr(&addr), &len);
+       if (err)
+               return err;
+
+       *c = xsocket(family, sotype, 0);
+       if (*c < 0)
+               return errno;
+       err = xconnect(*c, sockaddr(&addr), len);
+       if (err) {
+               err = errno;
+               goto close_cli0;
+       }
+
+       *p = xaccept_nonblock(s, NULL, NULL);
+       if (*p < 0) {
+               err = errno;
+               goto close_cli0;
+       }
+       return err;
+close_cli0:
+       close(*c);
+       return err;
+}
+
+static inline int create_socket_pairs(int s, int family, int sotype,
+                                     int *c0, int *c1, int *p0, int *p1)
+{
+       int err;
+
+       err = create_pair(s, family, sotype, c0, p0);
+       if (err)
+               return err;
+
+       err = create_pair(s, family, sotype, c1, p1);
+       if (err) {
+               close(*c0);
+               close(*p0);
+       }
+       return err;
+}
+
+static inline int enable_reuseport(int s, int progfd)
+{
+       int err, one = 1;
+
+       err = xsetsockopt(s, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one));
+       if (err)
+               return -1;
+       err = xsetsockopt(s, SOL_SOCKET, SO_ATTACH_REUSEPORT_EBPF, &progfd,
+                         sizeof(progfd));
+       if (err)
+               return -1;
+
+       return 0;
+}
+
+static inline int socket_loopback_reuseport(int family, int sotype, int progfd)
+{
+       struct sockaddr_storage addr;
+       socklen_t len;
+       int err, s;
+
+       init_addr_loopback(family, &addr, &len);
+
+       s = xsocket(family, sotype, 0);
+       if (s == -1)
+               return -1;
+
+       if (progfd >= 0)
+               enable_reuseport(s, progfd);
+
+       err = xbind(s, sockaddr(&addr), len);
+       if (err)
+               goto close;
+
+       if (sotype & SOCK_DGRAM)
+               return s;
+
+       err = xlisten(s, SOMAXCONN);
+       if (err)
+               goto close;
+
+       return s;
+close:
+       xclose(s);
+       return -1;
+}
+
+static inline int socket_loopback(int family, int sotype)
+{
+       return socket_loopback_reuseport(family, sotype, -1);
+}
+
+
 #endif // __SOCKMAP_HELPERS__

diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
index 7dc8dd7..b4f6f3a 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
@@ -29,58 +29,6 @@
 
 #include "sockmap_helpers.h"
 
-static int enable_reuseport(int s, int progfd)
-{
-       int err, one = 1;
-
-       err = xsetsockopt(s, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one));
-       if (err)
-               return -1;
-       err = xsetsockopt(s, SOL_SOCKET, SO_ATTACH_REUSEPORT_EBPF, &progfd,
-                         sizeof(progfd));
-       if (err)
-               return -1;
-
-       return 0;
-}
-
-static int socket_loopback_reuseport(int family, int sotype, int progfd)
-{
-       struct sockaddr_storage addr;
-       socklen_t len;
-       int err, s;
-
-       init_addr_loopback(family, &addr, &len);
-
-       s = xsocket(family, sotype, 0);
-       if (s == -1)
-               return -1;
-
-       if (progfd >= 0)
-               enable_reuseport(s, progfd);
-
-       err = xbind(s, sockaddr(&addr), len);
-       if (err)
-               goto close;
-
-       if (sotype & SOCK_DGRAM)
-               return s;
-
-       err = xlisten(s, SOMAXCONN);
-       if (err)
-               goto close;
-
-       return s;
-close:
-       xclose(s);
-       return -1;
-}
-
-static int socket_loopback(int family, int sotype)
-{
-       return socket_loopback_reuseport(family, sotype, -1);
-}
-
 static void test_insert_invalid(struct test_sockmap_listen *skel __always_unused,
                                int family, int sotype, int mapfd)
 {
@@ -723,31 +671,12 @@ static const char *redir_mode_str(enum redir_mode mode)
        }
 }
 
-static int add_to_sockmap(int sock_mapfd, int fd1, int fd2)
-{
-       u64 value;
-       u32 key;
-       int err;
-
-       key = 0;
-       value = fd1;
-       err = xbpf_map_update_elem(sock_mapfd, &key, &value, BPF_NOEXIST);
-       if (err)
-               return err;
-
-       key = 1;
-       value = fd2;
-       return xbpf_map_update_elem(sock_mapfd, &key, &value, BPF_NOEXIST);
-}
-
 static void redir_to_connected(int family, int sotype, int sock_mapfd,
                               int verd_mapfd, enum redir_mode mode)
 {
        const char *log_prefix = redir_mode_str(mode);
-       struct sockaddr_storage addr;
        int s, c0, c1, p0, p1;
        unsigned int pass;
-       socklen_t len;
        int err, n;
        u32 key;
        char b;
@@ -758,36 +687,13 @@ static void redir_to_connected(int family, int sotype, int sock_mapfd,
        if (s < 0)
                return;
 
-       len = sizeof(addr);
-       err = xgetsockname(s, sockaddr(&addr), &len);
+       err = create_socket_pairs(s, family, sotype, &c0, &c1, &p0, &p1);
        if (err)
                goto close_srv;
 
-       c0 = xsocket(family, sotype, 0);
-       if (c0 < 0)
-               goto close_srv;
-       err = xconnect(c0, sockaddr(&addr), len);
-       if (err)
-               goto close_cli0;
-
-       p0 = xaccept_nonblock(s, NULL, NULL);
-       if (p0 < 0)
-               goto close_cli0;
-
-       c1 = xsocket(family, sotype, 0);
-       if (c1 < 0)
-               goto close_peer0;
-       err = xconnect(c1, sockaddr(&addr), len);
-       if (err)
-               goto close_cli1;
-
-       p1 = xaccept_nonblock(s, NULL, NULL);
-       if (p1 < 0)
-               goto close_cli1;
-
        err = add_to_sockmap(sock_mapfd, p0, p1);
        if (err)
-               goto close_peer1;
+               goto close;
 
        n = write(mode == REDIR_INGRESS ? c1 : p1, "a", 1);
        if (n < 0)
@@ -795,12 +701,12 @@ static void redir_to_connected(int family, int sotype, int sock_mapfd,
        if (n == 0)
                FAIL("%s: incomplete write", log_prefix);
        if (n < 1)
-               goto close_peer1;
+               goto close;
 
        key = SK_PASS;
        err = xbpf_map_lookup_elem(verd_mapfd, &key, &pass);
        if (err)
-               goto close_peer1;
+               goto close;
        if (pass != 1)
                FAIL("%s: want pass count 1, have %d", log_prefix, pass);
        n = recv_timeout(c0, &b, 1, 0, IO_TIMEOUT_SEC);
@@ -809,13 +715,10 @@ static void redir_to_connected(int family, int sotype, int sock_mapfd,
        if (n == 0)
                FAIL("%s: incomplete recv", log_prefix);
 
-close_peer1:
+close:
        xclose(p1);
-close_cli1:
        xclose(c1);
-close_peer0:
        xclose(p0);
-close_cli0:
        xclose(c0);
 close_srv:
        xclose(s);