--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Test key rotation for TFO.
+ * New keys are 'rotated' in two steps:
+ * 1) Add new key as the 'backup' key 'behind' the primary key
+ * 2) Make new key the primary by swapping the backup and primary keys
+ *
+ * The rotation is done in stages using multiple sockets bound
+ * to the same port via SO_REUSEPORT. This simulates key rotation
+ * behind say a load balancer. We verify that across the rotation
+ * there are no cases in which a cookie is not accepted by verifying
+ * that TcpExtTCPFastOpenPassiveFail remains 0.
+ */
+#define _GNU_SOURCE
+#include <arpa/inet.h>
+#include <errno.h>
+#include <error.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/epoll.h>
+#include <unistd.h>
+#include <netinet/tcp.h>
+#include <fcntl.h>
+#include <time.h>
+
+#ifndef TCP_FASTOPEN_KEY
+#define TCP_FASTOPEN_KEY 33
+#endif
+
+#define N_LISTEN 10
+#define PROC_FASTOPEN_KEY "/proc/sys/net/ipv4/tcp_fastopen_key"
+#define KEY_LENGTH 16
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+#endif
+
+static bool do_ipv6;
+static bool do_sockopt;
+static bool do_rotate;
+static int key_len = KEY_LENGTH;
+static int rcv_fds[N_LISTEN];
+static int proc_fd;
+static const char *IP4_ADDR = "127.0.0.1";
+static const char *IP6_ADDR = "::1";
+static const int PORT = 8891;
+
+static void get_keys(int fd, uint32_t *keys)
+{
+ char buf[128];
+ int len = KEY_LENGTH * 2;
+
+ if (do_sockopt) {
+ if (getsockopt(fd, SOL_TCP, TCP_FASTOPEN_KEY, keys, &len))
+ error(1, errno, "Unable to get key");
+ return;
+ }
+ lseek(proc_fd, 0, SEEK_SET);
+ if (read(proc_fd, buf, sizeof(buf)) <= 0)
+ error(1, errno, "Unable to read %s", PROC_FASTOPEN_KEY);
+ if (sscanf(buf, "%x-%x-%x-%x,%x-%x-%x-%x", keys, keys + 1, keys + 2,
+ keys + 3, keys + 4, keys + 5, keys + 6, keys + 7) != 8)
+ error(1, 0, "Unable to parse %s", PROC_FASTOPEN_KEY);
+}
+
+static void set_keys(int fd, uint32_t *keys)
+{
+ char buf[128];
+
+ if (do_sockopt) {
+ if (setsockopt(fd, SOL_TCP, TCP_FASTOPEN_KEY, keys,
+ key_len))
+ error(1, errno, "Unable to set key");
+ return;
+ }
+ if (do_rotate)
+ snprintf(buf, 128, "%08x-%08x-%08x-%08x,%08x-%08x-%08x-%08x",
+ keys[0], keys[1], keys[2], keys[3], keys[4], keys[5],
+ keys[6], keys[7]);
+ else
+ snprintf(buf, 128, "%08x-%08x-%08x-%08x",
+ keys[0], keys[1], keys[2], keys[3]);
+ lseek(proc_fd, 0, SEEK_SET);
+ if (write(proc_fd, buf, sizeof(buf)) <= 0)
+ error(1, errno, "Unable to write %s", PROC_FASTOPEN_KEY);
+}
+
+static void build_rcv_fd(int family, int proto, int *rcv_fds)
+{
+ struct sockaddr_in addr4 = {0};
+ struct sockaddr_in6 addr6 = {0};
+ struct sockaddr *addr;
+ int opt = 1, i, sz;
+ int qlen = 100;
+ uint32_t keys[8];
+
+ switch (family) {
+ case AF_INET:
+ addr4.sin_family = family;
+ addr4.sin_addr.s_addr = htonl(INADDR_ANY);
+ addr4.sin_port = htons(PORT);
+ sz = sizeof(addr4);
+ addr = (struct sockaddr *)&addr4;
+ break;
+ case AF_INET6:
+ addr6.sin6_family = AF_INET6;
+ addr6.sin6_addr = in6addr_any;
+ addr6.sin6_port = htons(PORT);
+ sz = sizeof(addr6);
+ addr = (struct sockaddr *)&addr6;
+ break;
+ default:
+ error(1, 0, "Unsupported family %d", family);
+ /* clang does not recognize error() above as terminating
+ * the program, so it complains that saddr, sz are
+ * not initialized when this code path is taken. Silence it.
+ */
+ return;
+ }
+ for (i = 0; i < ARRAY_SIZE(keys); i++)
+ keys[i] = rand();
+ for (i = 0; i < N_LISTEN; i++) {
+ rcv_fds[i] = socket(family, proto, 0);
+ if (rcv_fds[i] < 0)
+ error(1, errno, "failed to create receive socket");
+ if (setsockopt(rcv_fds[i], SOL_SOCKET, SO_REUSEPORT, &opt,
+ sizeof(opt)))
+ error(1, errno, "failed to set SO_REUSEPORT");
+ if (bind(rcv_fds[i], addr, sz))
+ error(1, errno, "failed to bind receive socket");
+ if (setsockopt(rcv_fds[i], SOL_TCP, TCP_FASTOPEN, &qlen,
+ sizeof(qlen)))
+ error(1, errno, "failed to set TCP_FASTOPEN");
+ set_keys(rcv_fds[i], keys);
+ if (proto == SOCK_STREAM && listen(rcv_fds[i], 10))
+ error(1, errno, "failed to listen on receive port");
+ }
+}
+
+static int connect_and_send(int family, int proto)
+{
+ struct sockaddr_in saddr4 = {0};
+ struct sockaddr_in daddr4 = {0};
+ struct sockaddr_in6 saddr6 = {0};
+ struct sockaddr_in6 daddr6 = {0};
+ struct sockaddr *saddr, *daddr;
+ int fd, sz, ret;
+ char data[1];
+
+ switch (family) {
+ case AF_INET:
+ saddr4.sin_family = AF_INET;
+ saddr4.sin_addr.s_addr = htonl(INADDR_ANY);
+ saddr4.sin_port = 0;
+
+ daddr4.sin_family = AF_INET;
+ if (!inet_pton(family, IP4_ADDR, &daddr4.sin_addr.s_addr))
+ error(1, errno, "inet_pton failed: %s", IP4_ADDR);
+ daddr4.sin_port = htons(PORT);
+
+ sz = sizeof(saddr4);
+ saddr = (struct sockaddr *)&saddr4;
+ daddr = (struct sockaddr *)&daddr4;
+ break;
+ case AF_INET6:
+ saddr6.sin6_family = AF_INET6;
+ saddr6.sin6_addr = in6addr_any;
+
+ daddr6.sin6_family = AF_INET6;
+ if (!inet_pton(family, IP6_ADDR, &daddr6.sin6_addr))
+ error(1, errno, "inet_pton failed: %s", IP6_ADDR);
+ daddr6.sin6_port = htons(PORT);
+
+ sz = sizeof(saddr6);
+ saddr = (struct sockaddr *)&saddr6;
+ daddr = (struct sockaddr *)&daddr6;
+ break;
+ default:
+ error(1, 0, "Unsupported family %d", family);
+ /* clang does not recognize error() above as terminating
+ * the program, so it complains that saddr, daddr, sz are
+ * not initialized when this code path is taken. Silence it.
+ */
+ return -1;
+ }
+ fd = socket(family, proto, 0);
+ if (fd < 0)
+ error(1, errno, "failed to create send socket");
+ if (bind(fd, saddr, sz))
+ error(1, errno, "failed to bind send socket");
+ data[0] = 'a';
+ ret = sendto(fd, data, 1, MSG_FASTOPEN, daddr, sz);
+ if (ret != 1)
+ error(1, errno, "failed to sendto");
+
+ return fd;
+}
+
+static bool is_listen_fd(int fd)
+{
+ int i;
+
+ for (i = 0; i < N_LISTEN; i++) {
+ if (rcv_fds[i] == fd)
+ return true;
+ }
+ return false;
+}
+
+static int rotate_key(int fd)
+{
+ static int iter;
+ static uint32_t new_key[4];
+ uint32_t keys[8];
+ uint32_t tmp_key[4];
+ int i;
+ int len = KEY_LENGTH * 2;
+
+ if (iter < N_LISTEN) {
+ /* first set new key as backups */
+ if (iter == 0) {
+ for (i = 0; i < ARRAY_SIZE(new_key); i++)
+ new_key[i] = rand();
+ }
+ get_keys(fd, keys);
+ memcpy(keys + 4, new_key, KEY_LENGTH);
+ set_keys(fd, keys);
+ } else {
+ /* swap the keys */
+ get_keys(fd, keys);
+ memcpy(tmp_key, keys + 4, KEY_LENGTH);
+ memcpy(keys + 4, keys, KEY_LENGTH);
+ memcpy(keys, tmp_key, KEY_LENGTH);
+ set_keys(fd, keys);
+ }
+ if (++iter >= (N_LISTEN * 2))
+ iter = 0;
+}
+
+static void run_one_test(int family)
+{
+ struct epoll_event ev;
+ int i, send_fd;
+ int n_loops = 10000;
+ int rotate_key_fd = 0;
+ int key_rotate_interval = 50;
+ int fd, epfd;
+ char buf[1];
+
+ build_rcv_fd(family, SOCK_STREAM, rcv_fds);
+ epfd = epoll_create(1);
+ if (epfd < 0)
+ error(1, errno, "failed to create epoll");
+ ev.events = EPOLLIN;
+ for (i = 0; i < N_LISTEN; i++) {
+ ev.data.fd = rcv_fds[i];
+ if (epoll_ctl(epfd, EPOLL_CTL_ADD, rcv_fds[i], &ev))
+ error(1, errno, "failed to register sock epoll");
+ }
+ while (n_loops--) {
+ send_fd = connect_and_send(family, SOCK_STREAM);
+ if (do_rotate && ((n_loops % key_rotate_interval) == 0)) {
+ rotate_key(rcv_fds[rotate_key_fd]);
+ if (++rotate_key_fd >= N_LISTEN)
+ rotate_key_fd = 0;
+ }
+ while (1) {
+ i = epoll_wait(epfd, &ev, 1, -1);
+ if (i < 0)
+ error(1, errno, "epoll_wait failed");
+ if (is_listen_fd(ev.data.fd)) {
+ fd = accept(ev.data.fd, NULL, NULL);
+ if (fd < 0)
+ error(1, errno, "failed to accept");
+ ev.data.fd = fd;
+ if (epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev))
+ error(1, errno, "failed epoll add");
+ continue;
+ }
+ i = recv(ev.data.fd, buf, sizeof(buf), 0);
+ if (i != 1)
+ error(1, errno, "failed recv data");
+ if (epoll_ctl(epfd, EPOLL_CTL_DEL, ev.data.fd, NULL))
+ error(1, errno, "failed epoll del");
+ close(ev.data.fd);
+ break;
+ }
+ close(send_fd);
+ }
+ for (i = 0; i < N_LISTEN; i++)
+ close(rcv_fds[i]);
+}
+
+static void parse_opts(int argc, char **argv)
+{
+ int c;
+
+ while ((c = getopt(argc, argv, "46sr")) != -1) {
+ switch (c) {
+ case '4':
+ do_ipv6 = false;
+ break;
+ case '6':
+ do_ipv6 = true;
+ break;
+ case 's':
+ do_sockopt = true;
+ break;
+ case 'r':
+ do_rotate = true;
+ key_len = KEY_LENGTH * 2;
+ break;
+ default:
+ error(1, 0, "%s: parse error", argv[0]);
+ }
+ }
+}
+
+int main(int argc, char **argv)
+{
+ parse_opts(argc, argv);
+ proc_fd = open(PROC_FASTOPEN_KEY, O_RDWR);
+ if (proc_fd < 0)
+ error(1, errno, "Unable to open %s", PROC_FASTOPEN_KEY);
+ srand(time(NULL));
+ if (do_ipv6)
+ run_one_test(AF_INET6);
+ else
+ run_one_test(AF_INET);
+ close(proc_fd);
+ fprintf(stderr, "PASS\n");
+ return 0;
+}
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