selftests/bpf: Create established sockets in socket iterator tests

Prepare for bucket resume tests for established TCP sockets by creating
established sockets. Collect socket fds from connect() and accept()
sides and pass them to test cases.

Signed-off-by: Jordan Rife <[email protected]>
Signed-off-by: Martin KaFai Lau <[email protected]>
Acked-by: Stanislav Fomichev <[email protected]>

Author: jrife

tools/testing/selftests/bpf/prog_tests/sock_iter_batch.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 // Copyright (c) 2024 Meta
 
+#include <poll.h>
 #include <test_progs.h>
 #include "network_helpers.h"
 #include "sock_iter_batch.skel.h"
@@ -153,8 +154,71 @@ static void check_n_were_seen_once(int *fds, int fds_len, int n,
 	ASSERT_EQ(seen_once, n, "seen_once");
 }
 
+static int accept_from_one(struct pollfd *server_poll_fds,
+			   int server_poll_fds_len)
+{
+	static const int poll_timeout_ms = 5000; /* 5s */
+	int ret;
+	int i;
+
+	ret = poll(server_poll_fds, server_poll_fds_len, poll_timeout_ms);
+	if (!ASSERT_EQ(ret, 1, "poll"))
+		return -1;
+
+	for (i = 0; i < server_poll_fds_len; i++)
+		if (server_poll_fds[i].revents & POLLIN)
+			return accept(server_poll_fds[i].fd, NULL, NULL);
+
+	return -1;
+}
+
+static int *connect_to_server(int family, int sock_type, const char *addr,
+			      __u16 port, int nr_connects, int *server_fds,
+			      int server_fds_len)
+{
+	struct pollfd *server_poll_fds = NULL;
+	int *established_socks = NULL;
+	int i;
+
+	server_poll_fds = calloc(server_fds_len, sizeof(*server_poll_fds));
+	if (!ASSERT_OK_PTR(server_poll_fds, "server_poll_fds"))
+		return NULL;
+
+	for (i = 0; i < server_fds_len; i++) {
+		server_poll_fds[i].fd = server_fds[i];
+		server_poll_fds[i].events = POLLIN;
+	}
+
+	i = 0;
+
+	established_socks = malloc(sizeof(*established_socks) * nr_connects*2);
+	if (!ASSERT_OK_PTR(established_socks, "established_socks"))
+		goto error;
+
+	while (nr_connects--) {
+		established_socks[i] = connect_to_addr_str(family, sock_type,
+							   addr, port, NULL);
+		if (!ASSERT_OK_FD(established_socks[i], "connect_to_addr_str"))
+			goto error;
+		i++;
+		established_socks[i] = accept_from_one(server_poll_fds,
+						       server_fds_len);
+		if (!ASSERT_OK_FD(established_socks[i], "accept_from_one"))
+			goto error;
+		i++;
+	}
+
+	free(server_poll_fds);
+	return established_socks;
+error:
+	free_fds(established_socks, i);
+	free(server_poll_fds);
+	return NULL;
+}
+
 static void remove_seen(int family, int sock_type, const char *addr, __u16 port,
-			int *socks, int socks_len, struct sock_count *counts,
+			int *socks, int socks_len, int *established_socks,
+			int established_socks_len, struct sock_count *counts,
 			int counts_len, struct bpf_link *link, int iter_fd)
 {
 	int close_idx;
@@ -185,6 +249,7 @@ static void remove_seen(int family, int sock_type, const char *addr, __u16 port,
 
 static void remove_unseen(int family, int sock_type, const char *addr,
 			  __u16 port, int *socks, int socks_len,
+			  int *established_socks, int established_socks_len,
 			  struct sock_count *counts, int counts_len,
 			  struct bpf_link *link, int iter_fd)
 {
@@ -217,6 +282,7 @@ static void remove_unseen(int family, int sock_type, const char *addr,
 
 static void remove_all(int family, int sock_type, const char *addr,
 		       __u16 port, int *socks, int socks_len,
+		       int *established_socks, int established_socks_len,
 		       struct sock_count *counts, int counts_len,
 		       struct bpf_link *link, int iter_fd)
 {
@@ -244,7 +310,8 @@ static void remove_all(int family, int sock_type, const char *addr,
 }
 
 static void add_some(int family, int sock_type, const char *addr, __u16 port,
-		     int *socks, int socks_len, struct sock_count *counts,
+		     int *socks, int socks_len, int *established_socks,
+		     int established_socks_len, struct sock_count *counts,
 		     int counts_len, struct bpf_link *link, int iter_fd)
 {
 	int *new_socks = NULL;
@@ -274,6 +341,7 @@ static void add_some(int family, int sock_type, const char *addr, __u16 port,
 
 static void force_realloc(int family, int sock_type, const char *addr,
 			  __u16 port, int *socks, int socks_len,
+			  int *established_socks, int established_socks_len,
 			  struct sock_count *counts, int counts_len,
 			  struct bpf_link *link, int iter_fd)
 {
@@ -302,10 +370,12 @@ static void force_realloc(int family, int sock_type, const char *addr,
 
 struct test_case {
 	void (*test)(int family, int sock_type, const char *addr, __u16 port,
-		     int *socks, int socks_len, struct sock_count *counts,
+		     int *socks, int socks_len, int *established_socks,
+		     int established_socks_len, struct sock_count *counts,
 		     int counts_len, struct bpf_link *link, int iter_fd);
 	const char *description;
 	int ehash_buckets;
+	int connections;
 	int init_socks;
 	int max_socks;
 	int sock_type;
@@ -416,6 +486,7 @@ static void do_resume_test(struct test_case *tc)
 	static const __u16 port = 10001;
 	struct nstoken *nstoken = NULL;
 	struct bpf_link *link = NULL;
+	int *established_fds = NULL;
 	int err, iter_fd = -1;
 	const char *addr;
 	int *fds = NULL;
@@ -444,6 +515,14 @@ static void do_resume_test(struct test_case *tc)
 				     tc->init_socks);
 	if (!ASSERT_OK_PTR(fds, "start_reuseport_server"))
 		goto done;
+	if (tc->connections) {
+		established_fds = connect_to_server(tc->family, tc->sock_type,
+						    addr, port,
+						    tc->connections, fds,
+						    tc->init_socks);
+		if (!ASSERT_OK_PTR(established_fds, "connect_to_server"))
+			goto done;
+	}
 	skel->rodata->ports[0] = 0;
 	skel->rodata->ports[1] = 0;
 	skel->rodata->sf = tc->family;
@@ -465,13 +544,15 @@ static void do_resume_test(struct test_case *tc)
 		goto done;
 
 	tc->test(tc->family, tc->sock_type, addr, port, fds, tc->init_socks,
-		 counts, tc->max_socks, link, iter_fd);
+		 established_fds, tc->connections*2, counts, tc->max_socks,
+		 link, iter_fd);
 done:
 	close_netns(nstoken);
 	SYS_NOFAIL("ip netns del " TEST_CHILD_NS);
 	SYS_NOFAIL("sysctl -w net.ipv4.tcp_child_ehash_entries=0");
 	free(counts);
 	free_fds(fds, tc->init_socks);
+	free_fds(established_fds, tc->connections*2);
 	if (iter_fd >= 0)
 		close(iter_fd);
 	bpf_link__destroy(link);