--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Facebook */
+#include <test_progs.h>
+#include <linux/in6.h>
+#include <sys/socket.h>
+#include <sched.h>
+#include <unistd.h>
+#include "cgroup_helpers.h"
+#include "testing_helpers.h"
+#include "cgroup_tcp_skb.skel.h"
+#include "cgroup_tcp_skb.h"
+
+#define CGROUP_TCP_SKB_PATH "/test_cgroup_tcp_skb"
+
+static int install_filters(int cgroup_fd,
+ struct bpf_link **egress_link,
+ struct bpf_link **ingress_link,
+ struct bpf_program *egress_prog,
+ struct bpf_program *ingress_prog,
+ struct cgroup_tcp_skb *skel)
+{
+ /* Prepare filters */
+ skel->bss->g_sock_state = 0;
+ skel->bss->g_unexpected = 0;
+ *egress_link =
+ bpf_program__attach_cgroup(egress_prog,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(egress_link, "egress_link"))
+ return -1;
+ *ingress_link =
+ bpf_program__attach_cgroup(ingress_prog,
+ cgroup_fd);
+ if (!ASSERT_OK_PTR(ingress_link, "ingress_link"))
+ return -1;
+
+ return 0;
+}
+
+static void uninstall_filters(struct bpf_link **egress_link,
+ struct bpf_link **ingress_link)
+{
+ bpf_link__destroy(*egress_link);
+ *egress_link = NULL;
+ bpf_link__destroy(*ingress_link);
+ *ingress_link = NULL;
+}
+
+static int create_client_sock_v6(void)
+{
+ int fd;
+
+ fd = socket(AF_INET6, SOCK_STREAM, 0);
+ if (fd < 0) {
+ perror("socket");
+ return -1;
+ }
+
+ return fd;
+}
+
+static int create_server_sock_v6(void)
+{
+ struct sockaddr_in6 addr = {
+ .sin6_family = AF_INET6,
+ .sin6_port = htons(0),
+ .sin6_addr = IN6ADDR_LOOPBACK_INIT,
+ };
+ int fd, err;
+
+ fd = socket(AF_INET6, SOCK_STREAM, 0);
+ if (fd < 0) {
+ perror("socket");
+ return -1;
+ }
+
+ err = bind(fd, (struct sockaddr *)&addr, sizeof(addr));
+ if (err < 0) {
+ perror("bind");
+ return -1;
+ }
+
+ err = listen(fd, 1);
+ if (err < 0) {
+ perror("listen");
+ return -1;
+ }
+
+ return fd;
+}
+
+static int get_sock_port_v6(int fd)
+{
+ struct sockaddr_in6 addr;
+ socklen_t len;
+ int err;
+
+ len = sizeof(addr);
+ err = getsockname(fd, (struct sockaddr *)&addr, &len);
+ if (err < 0) {
+ perror("getsockname");
+ return -1;
+ }
+
+ return ntohs(addr.sin6_port);
+}
+
+static int connect_client_server_v6(int client_fd, int listen_fd)
+{
+ struct sockaddr_in6 addr = {
+ .sin6_family = AF_INET6,
+ .sin6_addr = IN6ADDR_LOOPBACK_INIT,
+ };
+ int err;
+
+ addr.sin6_port = htons(get_sock_port_v6(listen_fd));
+ if (addr.sin6_port < 0)
+ return -1;
+
+ err = connect(client_fd, (struct sockaddr *)&addr, sizeof(addr));
+ if (err < 0) {
+ perror("connect");
+ return -1;
+ }
+
+ return 0;
+}
+
+/* Connect to the server in a cgroup from the outside of the cgroup. */
+static int talk_to_cgroup(int *client_fd, int *listen_fd, int *service_fd,
+ struct cgroup_tcp_skb *skel)
+{
+ int err, cp;
+ char buf[5];
+
+ /* Create client & server socket */
+ err = join_root_cgroup();
+ if (!ASSERT_OK(err, "join_root_cgroup"))
+ return -1;
+ *client_fd = create_client_sock_v6();
+ if (!ASSERT_GE(*client_fd, 0, "client_fd"))
+ return -1;
+ err = join_cgroup(CGROUP_TCP_SKB_PATH);
+ if (!ASSERT_OK(err, "join_cgroup"))
+ return -1;
+ *listen_fd = create_server_sock_v6();
+ if (!ASSERT_GE(*listen_fd, 0, "listen_fd"))
+ return -1;
+ skel->bss->g_sock_port = get_sock_port_v6(*listen_fd);
+
+ /* Connect client to server */
+ err = connect_client_server_v6(*client_fd, *listen_fd);
+ if (!ASSERT_OK(err, "connect_client_server_v6"))
+ return -1;
+ *service_fd = accept(*listen_fd, NULL, NULL);
+ if (!ASSERT_GE(*service_fd, 0, "service_fd"))
+ return -1;
+ err = join_root_cgroup();
+ if (!ASSERT_OK(err, "join_root_cgroup"))
+ return -1;
+ cp = write(*client_fd, "hello", 5);
+ if (!ASSERT_EQ(cp, 5, "write"))
+ return -1;
+ cp = read(*service_fd, buf, 5);
+ if (!ASSERT_EQ(cp, 5, "read"))
+ return -1;
+
+ return 0;
+}
+
+/* Connect to the server out of a cgroup from inside the cgroup. */
+static int talk_to_outside(int *client_fd, int *listen_fd, int *service_fd,
+ struct cgroup_tcp_skb *skel)
+
+{
+ int err, cp;
+ char buf[5];
+
+ /* Create client & server socket */
+ err = join_root_cgroup();
+ if (!ASSERT_OK(err, "join_root_cgroup"))
+ return -1;
+ *listen_fd = create_server_sock_v6();
+ if (!ASSERT_GE(*listen_fd, 0, "listen_fd"))
+ return -1;
+ err = join_cgroup(CGROUP_TCP_SKB_PATH);
+ if (!ASSERT_OK(err, "join_cgroup"))
+ return -1;
+ *client_fd = create_client_sock_v6();
+ if (!ASSERT_GE(*client_fd, 0, "client_fd"))
+ return -1;
+ err = join_root_cgroup();
+ if (!ASSERT_OK(err, "join_root_cgroup"))
+ return -1;
+ skel->bss->g_sock_port = get_sock_port_v6(*listen_fd);
+
+ /* Connect client to server */
+ err = connect_client_server_v6(*client_fd, *listen_fd);
+ if (!ASSERT_OK(err, "connect_client_server_v6"))
+ return -1;
+ *service_fd = accept(*listen_fd, NULL, NULL);
+ if (!ASSERT_GE(*service_fd, 0, "service_fd"))
+ return -1;
+ cp = write(*client_fd, "hello", 5);
+ if (!ASSERT_EQ(cp, 5, "write"))
+ return -1;
+ cp = read(*service_fd, buf, 5);
+ if (!ASSERT_EQ(cp, 5, "read"))
+ return -1;
+
+ return 0;
+}
+
+static int close_connection(int *closing_fd, int *peer_fd, int *listen_fd,
+ struct cgroup_tcp_skb *skel)
+{
+ __u32 saved_packet_count = 0;
+ int err;
+ int i;
+
+ /* Wait for ACKs to be sent */
+ saved_packet_count = skel->bss->g_packet_count;
+ usleep(100000); /* 0.1s */
+ for (i = 0;
+ skel->bss->g_packet_count != saved_packet_count && i < 10;
+ i++) {
+ saved_packet_count = skel->bss->g_packet_count;
+ usleep(100000); /* 0.1s */
+ }
+ if (!ASSERT_EQ(skel->bss->g_packet_count, saved_packet_count,
+ "packet_count"))
+ return -1;
+
+ skel->bss->g_packet_count = 0;
+ saved_packet_count = 0;
+
+ /* Half shutdown to make sure the closing socket having a chance to
+ * receive a FIN from the peer.
+ */
+ err = shutdown(*closing_fd, SHUT_WR);
+ if (!ASSERT_OK(err, "shutdown closing_fd"))
+ return -1;
+
+ /* Wait for FIN and the ACK of the FIN to be observed */
+ for (i = 0;
+ skel->bss->g_packet_count < saved_packet_count + 2 && i < 10;
+ i++)
+ usleep(100000); /* 0.1s */
+ if (!ASSERT_GE(skel->bss->g_packet_count, saved_packet_count + 2,
+ "packet_count"))
+ return -1;
+
+ saved_packet_count = skel->bss->g_packet_count;
+
+ /* Fully shutdown the connection */
+ err = close(*peer_fd);
+ if (!ASSERT_OK(err, "close peer_fd"))
+ return -1;
+ *peer_fd = -1;
+
+ /* Wait for FIN and the ACK of the FIN to be observed */
+ for (i = 0;
+ skel->bss->g_packet_count < saved_packet_count + 2 && i < 10;
+ i++)
+ usleep(100000); /* 0.1s */
+ if (!ASSERT_GE(skel->bss->g_packet_count, saved_packet_count + 2,
+ "packet_count"))
+ return -1;
+
+ err = close(*closing_fd);
+ if (!ASSERT_OK(err, "close closing_fd"))
+ return -1;
+ *closing_fd = -1;
+
+ close(*listen_fd);
+ *listen_fd = -1;
+
+ return 0;
+}
+
+/* This test case includes four scenarios:
+ * 1. Connect to the server from outside the cgroup and close the connection
+ * from outside the cgroup.
+ * 2. Connect to the server from outside the cgroup and close the connection
+ * from inside the cgroup.
+ * 3. Connect to the server from inside the cgroup and close the connection
+ * from outside the cgroup.
+ * 4. Connect to the server from inside the cgroup and close the connection
+ * from inside the cgroup.
+ *
+ * The test case is to verify that cgroup_skb/{egress,ingress} filters
+ * receive expected packets including SYN, SYN/ACK, ACK, FIN, and FIN/ACK.
+ */
+void test_cgroup_tcp_skb(void)
+{
+ struct bpf_link *ingress_link = NULL;
+ struct bpf_link *egress_link = NULL;
+ int client_fd = -1, listen_fd = -1;
+ struct cgroup_tcp_skb *skel;
+ int service_fd = -1;
+ int cgroup_fd = -1;
+ int err;
+
+ skel = cgroup_tcp_skb__open_and_load();
+ if (!ASSERT_OK(!skel, "skel_open_load"))
+ return;
+
+ err = setup_cgroup_environment();
+ if (!ASSERT_OK(err, "setup_cgroup_environment"))
+ goto cleanup;
+
+ cgroup_fd = create_and_get_cgroup(CGROUP_TCP_SKB_PATH);
+ if (!ASSERT_GE(cgroup_fd, 0, "cgroup_fd"))
+ goto cleanup;
+
+ /* Scenario 1 */
+ err = install_filters(cgroup_fd, &egress_link, &ingress_link,
+ skel->progs.server_egress,
+ skel->progs.server_ingress,
+ skel);
+ if (!ASSERT_OK(err, "install_filters"))
+ goto cleanup;
+
+ err = talk_to_cgroup(&client_fd, &listen_fd, &service_fd, skel);
+ if (!ASSERT_OK(err, "talk_to_cgroup"))
+ goto cleanup;
+
+ err = close_connection(&client_fd, &service_fd, &listen_fd, skel);
+ if (!ASSERT_OK(err, "close_connection"))
+ goto cleanup;
+
+ ASSERT_EQ(skel->bss->g_unexpected, 0, "g_unexpected");
+ ASSERT_EQ(skel->bss->g_sock_state, CLOSED, "g_sock_state");
+
+ uninstall_filters(&egress_link, &ingress_link);
+
+ /* Scenario 2 */
+ err = install_filters(cgroup_fd, &egress_link, &ingress_link,
+ skel->progs.server_egress_srv,
+ skel->progs.server_ingress_srv,
+ skel);
+
+ err = talk_to_cgroup(&client_fd, &listen_fd, &service_fd, skel);
+ if (!ASSERT_OK(err, "talk_to_cgroup"))
+ goto cleanup;
+
+ err = close_connection(&service_fd, &client_fd, &listen_fd, skel);
+ if (!ASSERT_OK(err, "close_connection"))
+ goto cleanup;
+
+ ASSERT_EQ(skel->bss->g_unexpected, 0, "g_unexpected");
+ ASSERT_EQ(skel->bss->g_sock_state, TIME_WAIT, "g_sock_state");
+
+ uninstall_filters(&egress_link, &ingress_link);
+
+ /* Scenario 3 */
+ err = install_filters(cgroup_fd, &egress_link, &ingress_link,
+ skel->progs.client_egress_srv,
+ skel->progs.client_ingress_srv,
+ skel);
+
+ err = talk_to_outside(&client_fd, &listen_fd, &service_fd, skel);
+ if (!ASSERT_OK(err, "talk_to_outside"))
+ goto cleanup;
+
+ err = close_connection(&service_fd, &client_fd, &listen_fd, skel);
+ if (!ASSERT_OK(err, "close_connection"))
+ goto cleanup;
+
+ ASSERT_EQ(skel->bss->g_unexpected, 0, "g_unexpected");
+ ASSERT_EQ(skel->bss->g_sock_state, CLOSED, "g_sock_state");
+
+ uninstall_filters(&egress_link, &ingress_link);
+
+ /* Scenario 4 */
+ err = install_filters(cgroup_fd, &egress_link, &ingress_link,
+ skel->progs.client_egress,
+ skel->progs.client_ingress,
+ skel);
+
+ err = talk_to_outside(&client_fd, &listen_fd, &service_fd, skel);
+ if (!ASSERT_OK(err, "talk_to_outside"))
+ goto cleanup;
+
+ err = close_connection(&client_fd, &service_fd, &listen_fd, skel);
+ if (!ASSERT_OK(err, "close_connection"))
+ goto cleanup;
+
+ ASSERT_EQ(skel->bss->g_unexpected, 0, "g_unexpected");
+ ASSERT_EQ(skel->bss->g_sock_state, TIME_WAIT, "g_sock_state");
+
+ uninstall_filters(&egress_link, &ingress_link);
+
+cleanup:
+ close(client_fd);
+ close(listen_fd);
+ close(service_fd);
+ close(cgroup_fd);
+ bpf_link__destroy(egress_link);
+ bpf_link__destroy(ingress_link);
+ cleanup_cgroup_environment();
+ cgroup_tcp_skb__destroy(skel);
+}
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+#include <linux/bpf.h>
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_helpers.h>
+
+#include <linux/if_ether.h>
+#include <linux/in.h>
+#include <linux/in6.h>
+#include <linux/ipv6.h>
+#include <linux/tcp.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include "cgroup_tcp_skb.h"
+
+char _license[] SEC("license") = "GPL";
+
+__u16 g_sock_port = 0;
+__u32 g_sock_state = 0;
+int g_unexpected = 0;
+__u32 g_packet_count = 0;
+
+int needed_tcp_pkt(struct __sk_buff *skb, struct tcphdr *tcph)
+{
+ struct ipv6hdr ip6h;
+
+ if (skb->protocol != bpf_htons(ETH_P_IPV6))
+ return 0;
+ if (bpf_skb_load_bytes(skb, 0, &ip6h, sizeof(ip6h)))
+ return 0;
+
+ if (ip6h.nexthdr != IPPROTO_TCP)
+ return 0;
+
+ if (bpf_skb_load_bytes(skb, sizeof(ip6h), tcph, sizeof(*tcph)))
+ return 0;
+
+ if (tcph->source != bpf_htons(g_sock_port) &&
+ tcph->dest != bpf_htons(g_sock_port))
+ return 0;
+
+ return 1;
+}
+
+/* Run accept() on a socket in the cgroup to receive a new connection. */
+static int egress_accept(struct tcphdr *tcph)
+{
+ if (g_sock_state == SYN_RECV_SENDING_SYN_ACK) {
+ if (tcph->fin || !tcph->syn || !tcph->ack)
+ g_unexpected++;
+ else
+ g_sock_state = SYN_RECV;
+ return 1;
+ }
+
+ return 0;
+}
+
+static int ingress_accept(struct tcphdr *tcph)
+{
+ switch (g_sock_state) {
+ case INIT:
+ if (!tcph->syn || tcph->fin || tcph->ack)
+ g_unexpected++;
+ else
+ g_sock_state = SYN_RECV_SENDING_SYN_ACK;
+ break;
+ case SYN_RECV:
+ if (tcph->fin || tcph->syn || !tcph->ack)
+ g_unexpected++;
+ else
+ g_sock_state = ESTABLISHED;
+ break;
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Run connect() on a socket in the cgroup to start a new connection. */
+static int egress_connect(struct tcphdr *tcph)
+{
+ if (g_sock_state == INIT) {
+ if (!tcph->syn || tcph->fin || tcph->ack)
+ g_unexpected++;
+ else
+ g_sock_state = SYN_SENT;
+ return 1;
+ }
+
+ return 0;
+}
+
+static int ingress_connect(struct tcphdr *tcph)
+{
+ if (g_sock_state == SYN_SENT) {
+ if (tcph->fin || !tcph->syn || !tcph->ack)
+ g_unexpected++;
+ else
+ g_sock_state = ESTABLISHED;
+ return 1;
+ }
+
+ return 0;
+}
+
+/* The connection is closed by the peer outside the cgroup. */
+static int egress_close_remote(struct tcphdr *tcph)
+{
+ switch (g_sock_state) {
+ case ESTABLISHED:
+ break;
+ case CLOSE_WAIT_SENDING_ACK:
+ if (tcph->fin || tcph->syn || !tcph->ack)
+ g_unexpected++;
+ else
+ g_sock_state = CLOSE_WAIT;
+ break;
+ case CLOSE_WAIT:
+ if (!tcph->fin)
+ g_unexpected++;
+ else
+ g_sock_state = LAST_ACK;
+ break;
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+static int ingress_close_remote(struct tcphdr *tcph)
+{
+ switch (g_sock_state) {
+ case ESTABLISHED:
+ if (tcph->fin)
+ g_sock_state = CLOSE_WAIT_SENDING_ACK;
+ break;
+ case LAST_ACK:
+ if (tcph->fin || tcph->syn || !tcph->ack)
+ g_unexpected++;
+ else
+ g_sock_state = CLOSED;
+ break;
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+/* The connection is closed by the endpoint inside the cgroup. */
+static int egress_close_local(struct tcphdr *tcph)
+{
+ switch (g_sock_state) {
+ case ESTABLISHED:
+ if (tcph->fin)
+ g_sock_state = FIN_WAIT1;
+ break;
+ case TIME_WAIT_SENDING_ACK:
+ if (tcph->fin || tcph->syn || !tcph->ack)
+ g_unexpected++;
+ else
+ g_sock_state = TIME_WAIT;
+ break;
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+static int ingress_close_local(struct tcphdr *tcph)
+{
+ switch (g_sock_state) {
+ case ESTABLISHED:
+ break;
+ case FIN_WAIT1:
+ if (tcph->fin || tcph->syn || !tcph->ack)
+ g_unexpected++;
+ else
+ g_sock_state = FIN_WAIT2;
+ break;
+ case FIN_WAIT2:
+ if (!tcph->fin || tcph->syn || !tcph->ack)
+ g_unexpected++;
+ else
+ g_sock_state = TIME_WAIT_SENDING_ACK;
+ break;
+ default:
+ return 0;
+ }
+
+ return 1;
+}
+
+/* Check the types of outgoing packets of a server socket to make sure they
+ * are consistent with the state of the server socket.
+ *
+ * The connection is closed by the client side.
+ */
+SEC("cgroup_skb/egress")
+int server_egress(struct __sk_buff *skb)
+{
+ struct tcphdr tcph;
+
+ if (!needed_tcp_pkt(skb, &tcph))
+ return 1;
+
+ g_packet_count++;
+
+ /* Egress of the server socket. */
+ if (egress_accept(&tcph) || egress_close_remote(&tcph))
+ return 1;
+
+ g_unexpected++;
+ return 1;
+}
+
+/* Check the types of incoming packets of a server socket to make sure they
+ * are consistent with the state of the server socket.
+ *
+ * The connection is closed by the client side.
+ */
+SEC("cgroup_skb/ingress")
+int server_ingress(struct __sk_buff *skb)
+{
+ struct tcphdr tcph;
+
+ if (!needed_tcp_pkt(skb, &tcph))
+ return 1;
+
+ g_packet_count++;
+
+ /* Ingress of the server socket. */
+ if (ingress_accept(&tcph) || ingress_close_remote(&tcph))
+ return 1;
+
+ g_unexpected++;
+ return 1;
+}
+
+/* Check the types of outgoing packets of a server socket to make sure they
+ * are consistent with the state of the server socket.
+ *
+ * The connection is closed by the server side.
+ */
+SEC("cgroup_skb/egress")
+int server_egress_srv(struct __sk_buff *skb)
+{
+ struct tcphdr tcph;
+
+ if (!needed_tcp_pkt(skb, &tcph))
+ return 1;
+
+ g_packet_count++;
+
+ /* Egress of the server socket. */
+ if (egress_accept(&tcph) || egress_close_local(&tcph))
+ return 1;
+
+ g_unexpected++;
+ return 1;
+}
+
+/* Check the types of incoming packets of a server socket to make sure they
+ * are consistent with the state of the server socket.
+ *
+ * The connection is closed by the server side.
+ */
+SEC("cgroup_skb/ingress")
+int server_ingress_srv(struct __sk_buff *skb)
+{
+ struct tcphdr tcph;
+
+ if (!needed_tcp_pkt(skb, &tcph))
+ return 1;
+
+ g_packet_count++;
+
+ /* Ingress of the server socket. */
+ if (ingress_accept(&tcph) || ingress_close_local(&tcph))
+ return 1;
+
+ g_unexpected++;
+ return 1;
+}
+
+/* Check the types of outgoing packets of a client socket to make sure they
+ * are consistent with the state of the client socket.
+ *
+ * The connection is closed by the server side.
+ */
+SEC("cgroup_skb/egress")
+int client_egress_srv(struct __sk_buff *skb)
+{
+ struct tcphdr tcph;
+
+ if (!needed_tcp_pkt(skb, &tcph))
+ return 1;
+
+ g_packet_count++;
+
+ /* Egress of the server socket. */
+ if (egress_connect(&tcph) || egress_close_remote(&tcph))
+ return 1;
+
+ g_unexpected++;
+ return 1;
+}
+
+/* Check the types of incoming packets of a client socket to make sure they
+ * are consistent with the state of the client socket.
+ *
+ * The connection is closed by the server side.
+ */
+SEC("cgroup_skb/ingress")
+int client_ingress_srv(struct __sk_buff *skb)
+{
+ struct tcphdr tcph;
+
+ if (!needed_tcp_pkt(skb, &tcph))
+ return 1;
+
+ g_packet_count++;
+
+ /* Ingress of the server socket. */
+ if (ingress_connect(&tcph) || ingress_close_remote(&tcph))
+ return 1;
+
+ g_unexpected++;
+ return 1;
+}
+
+/* Check the types of outgoing packets of a client socket to make sure they
+ * are consistent with the state of the client socket.
+ *
+ * The connection is closed by the client side.
+ */
+SEC("cgroup_skb/egress")
+int client_egress(struct __sk_buff *skb)
+{
+ struct tcphdr tcph;
+
+ if (!needed_tcp_pkt(skb, &tcph))
+ return 1;
+
+ g_packet_count++;
+
+ /* Egress of the server socket. */
+ if (egress_connect(&tcph) || egress_close_local(&tcph))
+ return 1;
+
+ g_unexpected++;
+ return 1;
+}
+
+/* Check the types of incoming packets of a client socket to make sure they
+ * are consistent with the state of the client socket.
+ *
+ * The connection is closed by the client side.
+ */
+SEC("cgroup_skb/ingress")
+int client_ingress(struct __sk_buff *skb)
+{
+ struct tcphdr tcph;
+
+ if (!needed_tcp_pkt(skb, &tcph))
+ return 1;
+
+ g_packet_count++;
+
+ /* Ingress of the server socket. */
+ if (ingress_connect(&tcph) || ingress_close_local(&tcph))
+ return 1;
+
+ g_unexpected++;
+ return 1;
+}