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-rw-r--r--dev/udp/udp-perturb.c527
1 files changed, 527 insertions, 0 deletions
diff --git a/dev/udp/udp-perturb.c b/dev/udp/udp-perturb.c
new file mode 100644
index 0000000..55d1773
--- /dev/null
+++ b/dev/udp/udp-perturb.c
@@ -0,0 +1,527 @@
+/*
+ * Copyright (C) 2010-2022 Willy Tarreau <w@1wt.eu>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/tcp.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <getopt.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <limits.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+#define MAXCONN 1
+
+const int zero = 0;
+const int one = 1;
+
+struct conn {
+ struct sockaddr_storage cli_addr;
+ int fd_bck;
+};
+
+struct errmsg {
+ char *msg;
+ int size;
+ int len;
+};
+
+struct sockaddr_storage frt_addr; // listen address
+struct sockaddr_storage srv_addr; // server address
+
+#define MAXPKTSIZE 16384
+#define MAXREORDER 20
+char trash[MAXPKTSIZE];
+
+/* history buffer, to resend random packets */
+struct {
+ char buf[MAXPKTSIZE];
+ size_t len;
+} history[MAXREORDER];
+int history_idx = 0;
+unsigned int rand_rate = 0;
+unsigned int corr_rate = 0;
+unsigned int corr_span = 1;
+unsigned int corr_base = 0;
+
+struct conn conns[MAXCONN]; // sole connection for now
+int fd_frt;
+
+int nbfd = 0;
+int nbconn = MAXCONN;
+
+
+/* display the message and exit with the code */
+__attribute__((noreturn)) void die(int code, const char *format, ...)
+{
+ va_list args;
+
+ va_start(args, format);
+ vfprintf(stderr, format, args);
+ va_end(args);
+ exit(code);
+}
+
+/* Xorshift RNG */
+unsigned int prng_state = ~0U/3; // half bits set, but any seed will fit
+static inline unsigned int prng(unsigned int range)
+{
+ unsigned int x = prng_state;
+
+ x ^= x << 13;
+ x ^= x >> 17;
+ x ^= x << 5;
+ prng_state = x;
+ return ((unsigned long long)x * (range - 1) + x) >> 32;
+}
+
+/* converts str in the form [<ipv4>|<ipv6>|<hostname>]:port to struct sockaddr_storage.
+ * Returns < 0 with err set in case of error.
+ */
+int addr_to_ss(char *str, struct sockaddr_storage *ss, struct errmsg *err)
+{
+ char *port_str;
+ int port;
+
+ /* look for the addr/port delimiter, it's the last colon. */
+ if ((port_str = strrchr(str, ':')) == NULL)
+ port_str = str;
+ else
+ *port_str++ = 0;
+
+ port = atoi(port_str);
+ if (port <= 0 || port > 65535) {
+ err->len = snprintf(err->msg, err->size, "Missing/invalid port number: '%s'\n", port_str);
+ return -1;
+ }
+ *port_str = 0; // present an empty address if none was set
+
+ memset(ss, 0, sizeof(*ss));
+
+ if (strrchr(str, ':') != NULL) {
+ /* IPv6 address contains ':' */
+ ss->ss_family = AF_INET6;
+ ((struct sockaddr_in6 *)ss)->sin6_port = htons(port);
+
+ if (!inet_pton(ss->ss_family, str, &((struct sockaddr_in6 *)ss)->sin6_addr)) {
+ err->len = snprintf(err->msg, err->size, "Invalid IPv6 server address: '%s'", str);
+ return -1;
+ }
+ }
+ else {
+ ss->ss_family = AF_INET;
+ ((struct sockaddr_in *)ss)->sin_port = htons(port);
+
+ if (*str == '*' || *str == '\0') { /* INADDR_ANY */
+ ((struct sockaddr_in *)ss)->sin_addr.s_addr = INADDR_ANY;
+ return 0;
+ }
+
+ if (!inet_pton(ss->ss_family, str, &((struct sockaddr_in *)ss)->sin_addr)) {
+ struct hostent *he = gethostbyname(str);
+
+ if (he == NULL) {
+ err->len = snprintf(err->msg, err->size, "Invalid IPv4 server name: '%s'", str);
+ return -1;
+ }
+ ((struct sockaddr_in *)ss)->sin_addr = *(struct in_addr *) *(he->h_addr_list);
+ }
+ }
+ return 0;
+}
+
+/* returns <0 with err in case of error or the front FD */
+int create_udp_listener(struct sockaddr_storage *addr, struct errmsg *err)
+{
+ int fd;
+
+ if ((fd = socket(addr->ss_family, SOCK_DGRAM, 0)) == -1) {
+ err->len = snprintf(err->msg, err->size, "socket(): '%s'", strerror(errno));
+ goto fail;
+ }
+
+ if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1) {
+ err->len = snprintf(err->msg, err->size, "fcntl(O_NONBLOCK): '%s'", strerror(errno));
+ goto fail;
+ }
+
+ if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &one, sizeof(one)) == -1) {
+ err->len = snprintf(err->msg, err->size, "setsockopt(SO_REUSEADDR): '%s'", strerror(errno));
+ goto fail;
+ }
+
+#ifdef SO_REUSEPORT
+ if (setsockopt(fd, SOL_SOCKET, SO_REUSEPORT, (char *) &one, sizeof(one)) == -1) {
+ err->len = snprintf(err->msg, err->size, "setsockopt(SO_REUSEPORT): '%s'", strerror(errno));
+ goto fail;
+ }
+#endif
+ if (bind(fd, (struct sockaddr *)addr, addr->ss_family == AF_INET6 ?
+ sizeof(struct sockaddr_in6) : sizeof(struct sockaddr_in)) == -1) {
+ err->len = snprintf(err->msg, err->size, "bind(): '%s'", strerror(errno));
+ goto fail;
+ }
+
+ /* the socket is ready */
+ return fd;
+
+ fail:
+ if (fd > -1)
+ close(fd);
+ fd = -1;
+ return fd;
+}
+
+/* recompute pollfds using frt_fd and scanning nbconn connections.
+ * Returns the number of FDs in the set.
+ */
+int update_pfd(struct pollfd *pfd, int frt_fd, struct conn *conns, int nbconn)
+{
+ int nbfd = 0;
+ int i;
+
+ pfd[nbfd].fd = frt_fd;
+ pfd[nbfd].events = POLLIN;
+ nbfd++;
+
+ for (i = 0; i < nbconn; i++) {
+ if (conns[i].fd_bck < 0)
+ continue;
+ pfd[nbfd].fd = conns[i].fd_bck;
+ pfd[nbfd].events = POLLIN;
+ nbfd++;
+ }
+ return nbfd;
+}
+
+/* searches a connection using fd <fd> as back connection, returns it if found
+ * otherwise NULL.
+ */
+struct conn *conn_bck_lookup(struct conn *conns, int nbconn, int fd)
+{
+ int i;
+
+ for (i = 0; i < nbconn; i++) {
+ if (conns[i].fd_bck < 0)
+ continue;
+ if (conns[i].fd_bck == fd)
+ return &conns[i];
+ }
+ return NULL;
+}
+
+/* Try to establish a connection to <sa>. Return the fd or -1 in case of error */
+int add_connection(struct sockaddr_storage *ss)
+{
+ int fd;
+
+ fd = socket(ss->ss_family, SOCK_DGRAM, 0);
+ if (fd < 0)
+ goto fail;
+
+ if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1)
+ goto fail;
+
+ if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)) == -1)
+ goto fail;
+
+ if (connect(fd, (struct sockaddr *)ss, ss->ss_family == AF_INET6 ?
+ sizeof(struct sockaddr_in6) : sizeof(struct sockaddr_in)) == -1) {
+ if (errno != EINPROGRESS)
+ goto fail;
+ }
+
+ return fd;
+ fail:
+ if (fd > -1)
+ close(fd);
+ return -1;
+}
+
+/* Corrupt <buf> buffer with <buflen> as length if required */
+static void pktbuf_apply_corruption(char *buf, size_t buflen)
+{
+ if (corr_rate > 0 && prng(100) < corr_rate) {
+ unsigned int rnd = prng(corr_span * 256); // pos and value
+ unsigned int pos = corr_base + (rnd >> 8);
+
+ if (pos < buflen)
+ buf[pos] ^= rnd;
+ }
+}
+
+/* Handle a read operation on an front FD. Will either reuse the existing
+ * connection if the source is found, or will allocate a new one, possibly
+ * replacing the oldest one. Returns <0 on error or the number of bytes
+ * transmitted.
+ */
+int handle_frt(int fd, struct pollfd *pfd, struct conn *conns, int nbconn)
+{
+ struct sockaddr_storage addr;
+ socklen_t addrlen;
+ struct conn *conn;
+ char *pktbuf = trash;
+ int ret;
+ int i;
+
+ if (rand_rate > 0) {
+ /* keep a copy of this packet */
+ history_idx++;
+ if (history_idx >= MAXREORDER)
+ history_idx = 0;
+ pktbuf = history[history_idx].buf;
+ }
+
+ addrlen = sizeof(addr);
+ ret = recvfrom(fd, pktbuf, MAXPKTSIZE, MSG_DONTWAIT | MSG_NOSIGNAL,
+ (struct sockaddr *)&addr, &addrlen);
+
+ if (rand_rate > 0) {
+ history[history_idx].len = ret; // note: we may store -1/EAGAIN
+ if (prng(100) < rand_rate) {
+ /* return a random buffer or nothing */
+ int idx = prng(MAXREORDER + 1) - 1;
+ if (idx < 0) {
+ /* pretend we didn't receive anything */
+ return 0;
+ }
+ pktbuf = history[idx].buf;
+ ret = history[idx].len;
+ if (ret < 0)
+ errno = EAGAIN;
+ }
+ }
+
+ if (ret == 0)
+ return 0;
+
+ if (ret < 0)
+ return errno == EAGAIN ? 0 : -1;
+
+ pktbuf_apply_corruption(pktbuf, ret);
+
+ conn = NULL;
+ for (i = 0; i < nbconn; i++) {
+ if (addr.ss_family != conns[i].cli_addr.ss_family)
+ continue;
+ if (memcmp(&conns[i].cli_addr, &addr,
+ (addr.ss_family == AF_INET6) ?
+ sizeof(struct sockaddr_in6) :
+ sizeof(struct sockaddr_in)) != 0)
+ continue;
+ conn = &conns[i];
+ break;
+ }
+
+ if (!conn) {
+ /* address not found, create a new conn or replace the oldest
+ * one. For now we support a single one.
+ */
+ conn = &conns[0];
+
+ memcpy(&conn->cli_addr, &addr,
+ (addr.ss_family == AF_INET6) ?
+ sizeof(struct sockaddr_in6) :
+ sizeof(struct sockaddr_in));
+
+ if (conn->fd_bck < 0) {
+ /* try to create a new connection */
+ conn->fd_bck = add_connection(&srv_addr);
+ nbfd = update_pfd(pfd, fd, conns, nbconn); // FIXME: MAXCONN instead ?
+ }
+ }
+
+ if (conn->fd_bck < 0)
+ return 0;
+
+ ret = send(conn->fd_bck, pktbuf, ret, MSG_DONTWAIT | MSG_NOSIGNAL);
+ return ret;
+}
+
+/* Handle a read operation on an FD. Close and return 0 when the read returns zero or an error */
+int handle_bck(int fd, struct pollfd *pfd, struct conn *conns, int nbconn)
+{
+ struct sockaddr_storage addr;
+ socklen_t addrlen;
+ struct conn *conn;
+ char *pktbuf = trash;
+ int ret;
+
+ if (rand_rate > 0) {
+ /* keep a copy of this packet */
+ history_idx++;
+ if (history_idx >= MAXREORDER)
+ history_idx = 0;
+ pktbuf = history[history_idx].buf;
+ }
+
+ ret = recvfrom(fd, pktbuf, MAXPKTSIZE, MSG_DONTWAIT | MSG_NOSIGNAL,
+ (struct sockaddr *)&addr, &addrlen);
+
+ if (rand_rate > 0) {
+ history[history_idx].len = ret; // note: we may store -1/EAGAIN
+ if (prng(100) < rand_rate) {
+ /* return a random buffer or nothing */
+ int idx = prng(MAXREORDER + 1) - 1;
+ if (idx < 0) {
+ /* pretend we didn't receive anything */
+ return 0;
+ }
+ pktbuf = history[idx].buf;
+ ret = history[idx].len;
+ if (ret < 0)
+ errno = EAGAIN;
+ }
+ }
+
+ if (ret == 0)
+ return 0;
+
+ if (ret < 0)
+ return errno == EAGAIN ? 0 : -1;
+
+ pktbuf_apply_corruption(pktbuf, ret);
+
+ conn = conn_bck_lookup(conns, nbconn, fd);
+ if (!conn)
+ return 0;
+
+ ret = sendto(fd_frt, pktbuf, ret, MSG_DONTWAIT | MSG_NOSIGNAL,
+ (struct sockaddr *)&conn->cli_addr,
+ conn->cli_addr.ss_family == AF_INET6 ?
+ sizeof(struct sockaddr_in6) : sizeof(struct sockaddr_in));
+ return ret;
+}
+
+/* print the usage message for program named <name> and exit with status <status> */
+void usage(int status, const char *name)
+{
+ if (strchr(name, '/'))
+ name = strrchr(name, '/') + 1;
+ die(status,
+ "Usage: %s [-h] [options] [<laddr>:]<lport> [<saddr>:]<sport>\n"
+ "Options:\n"
+ " -h display this help\n"
+ " -r rate reorder/duplicate/lose around <rate>%% of packets\n"
+ " -s seed force initial random seed (currently %#x)\n"
+ " -c rate corrupt around <rate>%% of packets\n"
+ " -o ofs start offset of corrupted area (def: 0)\n"
+ " -w width width of the corrupted area (def: 1)\n"
+ "", name, prng_state);
+}
+
+int main(int argc, char **argv)
+{
+ struct errmsg err;
+ struct pollfd *pfd;
+ int opt;
+ int i;
+
+ err.len = 0;
+ err.size = 100;
+ err.msg = malloc(err.size);
+
+ while ((opt = getopt(argc, argv, "hr:s:c:o:w:")) != -1) {
+ switch (opt) {
+ case 'r': // rand_rate%
+ rand_rate = atoi(optarg);
+ break;
+ case 's': // seed
+ prng_state = atol(optarg);
+ break;
+ case 'c': // corruption rate
+ corr_rate = atol(optarg);
+ break;
+ case 'o': // corruption offset
+ corr_base = atol(optarg);
+ break;
+ case 'w': // corruption width
+ corr_span = atol(optarg);
+ break;
+ default: // help, anything else
+ usage(0, argv[0]);
+ }
+ }
+
+ if (argc - optind < 2)
+ usage(1, argv[0]);
+
+ if (addr_to_ss(argv[optind], &frt_addr, &err) < 0)
+ die(1, "parsing listen address: %s\n", err.msg);
+
+ if (addr_to_ss(argv[optind+1], &srv_addr, &err) < 0)
+ die(1, "parsing server address: %s\n", err.msg);
+
+ pfd = calloc(MAXCONN + 1, sizeof(struct pollfd));
+ if (!pfd)
+ die(1, "out of memory\n");
+
+ fd_frt = create_udp_listener(&frt_addr, &err);
+ if (fd_frt < 0)
+ die(1, "binding listener: %s\n", err.msg);
+
+
+ for (i = 0; i < MAXCONN; i++)
+ conns[i].fd_bck = -1;
+
+ nbfd = update_pfd(pfd, fd_frt, conns, MAXCONN);
+
+ while (1) {
+ /* listen for incoming packets */
+ int ret, i;
+
+ ret = poll(pfd, nbfd, 1000);
+ if (ret <= 0)
+ continue;
+
+ for (i = 0; ret; i++) {
+ if (!pfd[i].revents)
+ continue;
+ ret--;
+
+ if (pfd[i].fd == fd_frt) {
+ handle_frt(pfd[i].fd, pfd, conns, nbconn);
+ continue;
+ }
+
+ handle_bck(pfd[i].fd, pfd, conns, nbconn);
+ }
+ }
+}
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