]> git.ipfire.org Git - thirdparty/asterisk.git/commitdiff
res_rtp_asterisk: Add a DEVMODE RTP drop packets CLI command
authorKevin Harwell <kharwell@sangoma.com>
Fri, 5 Mar 2021 18:53:47 +0000 (12:53 -0600)
committerGeorge Joseph <gjoseph@digium.com>
Wed, 31 Mar 2021 16:54:17 +0000 (11:54 -0500)
This patch makes it so when Asterisk is compiled in DEVMODE a CLI
command is available that allows someone to drop incoming RTP
packets. The command allows for dropping of packets once, or on a
timed interval (e.g. drop 10 packets every 5 seconds). A user can
also specify to drop packets by IP address.

Change-Id: I25fa7ae9bad6ed68e273bbcccf0ee51cae6e7024

res/res_rtp_asterisk.c

index b0a3f2a400e2c6d9a8117a2c1d4438c923fde7af..ac01d39ed6b308d4a09cbf69192ceb919719a567 100644 (file)
@@ -63,6 +63,7 @@
 #include <ifaddrs.h>
 #endif
 
+#include "asterisk/conversions.h"
 #include "asterisk/options.h"
 #include "asterisk/logger_category.h"
 #include "asterisk/stun.h"
@@ -7529,6 +7530,113 @@ static struct ast_frame *ast_rtp_interpret(struct ast_rtp_instance *instance, st
        return AST_LIST_FIRST(&frames);
 }
 
+#ifdef AST_DEVMODE
+
+struct rtp_drop_packets_data {
+       /* Whether or not to randomize the number of packets to drop. */
+       unsigned int use_random_num;
+       /* Whether or not to randomize the time interval between packets drops. */
+       unsigned int use_random_interval;
+       /* The total number of packets to drop. If 'use_random_num' is true then this
+        * value becomes the upper bound for a number of random packets to drop. */
+       unsigned int num_to_drop;
+       /* The current number of packets that have been dropped during an interval. */
+       unsigned int num_dropped;
+       /* The optional interval to use between packet drops. If 'use_random_interval'
+        * is true then this values becomes the upper bound for a random interval used. */
+       struct timeval interval;
+       /* The next time a packet drop should be triggered. */
+       struct timeval next;
+       /* An optional IP address from which to drop packets from. */
+       struct ast_sockaddr addr;
+       /* The optional port from which to drop packets from. */
+       unsigned int port;
+} drop_packets_data;
+
+static void drop_packets_data_update(struct timeval tv)
+{
+       /*
+        * num_dropped keeps up with the number of packets that have been dropped for a
+        * given interval. Once the specified number of packets have been dropped and
+        * the next time interval is ready to trigger then set this number to zero (drop
+        * the next 'n' packets up to 'num_to_drop'), or if 'use_random_num' is set to
+        * true then set to a random number between zero and 'num_to_drop'.
+        */
+       drop_packets_data.num_dropped = drop_packets_data.use_random_num ?
+               ast_random() % drop_packets_data.num_to_drop : 0;
+
+       /*
+        * A specified number of packets can be dropped at a given interval (e.g every
+        * 30 seconds). If 'use_random_interval' is false simply add the interval to
+        * the given time to get the next trigger point. If set to true, then get a
+        * random time between the given time and up to the specified interval.
+        */
+       if (drop_packets_data.use_random_interval) {
+               /* Calculate as a percentage of the specified drop packets interval */
+               struct timeval interval = ast_time_create_by_unit(ast_time_tv_to_usec(
+                       &drop_packets_data.interval) * ((double)(ast_random() % 100 + 1) / 100),
+                       TIME_UNIT_MICROSECOND);
+
+               drop_packets_data.next = ast_tvadd(tv, interval);
+       } else {
+               drop_packets_data.next = ast_tvadd(tv, drop_packets_data.interval);
+       }
+}
+
+static int should_drop_packets(struct ast_sockaddr *addr)
+{
+       struct timeval tv;
+
+       if (!drop_packets_data.num_to_drop) {
+               return 0;
+       }
+
+       /*
+        * If an address has been specified then filter on it, and also the port if
+        * it too was included.
+        */
+       if (!ast_sockaddr_isnull(&drop_packets_data.addr) &&
+               (drop_packets_data.port ?
+                       ast_sockaddr_cmp(&drop_packets_data.addr, addr) :
+                       ast_sockaddr_cmp_addr(&drop_packets_data.addr, addr)) != 0) {
+               /* Address and/or port does not match */
+               return 0;
+       }
+
+       /* Keep dropping packets until we've reached the total to drop */
+       if (drop_packets_data.num_dropped < drop_packets_data.num_to_drop) {
+               ++drop_packets_data.num_dropped;
+               return 1;
+       }
+
+       /*
+        * Once the set number of packets has been dropped check to see if it's
+        * time to drop more.
+        */
+
+       if (ast_tvzero(drop_packets_data.interval)) {
+               /* If no interval then drop specified number of packets and be done */
+               drop_packets_data.num_to_drop = 0;
+               return 0;
+       }
+
+       tv = ast_tvnow();
+       if (ast_tvcmp(tv, drop_packets_data.next) == -1) {
+               /* Still waiting for the next time interval to elapse */
+               return 0;
+       }
+
+       /*
+        * The next time interval has elapsed so update the tracking structure
+        * in order to start dropping more packets, and figure out when the next
+        * time interval is.
+        */
+       drop_packets_data_update(tv);
+       return 1;
+}
+
+#endif
+
 /*! \pre instance is locked */
 static struct ast_frame *ast_rtp_read(struct ast_rtp_instance *instance, int rtcp)
 {
@@ -7823,6 +7931,14 @@ static struct ast_frame *ast_rtp_read(struct ast_rtp_instance *instance, int rtc
        seqno &= 0xffff;
        timestamp = ntohl(rtpheader[1]);
 
+#ifdef AST_DEVMODE
+       if (should_drop_packets(&addr)) {
+               ast_debug(0, "(%p) RTP: drop received packet from %s (type %-2.2d, seq %-6.6u, ts %-6.6u, len %-6.6d)\n",
+                       instance, ast_sockaddr_stringify(&addr), payloadtype, seqno, timestamp, res - hdrlen);
+               return &ast_null_frame;
+       }
+#endif
+
        if (rtp_debug_test_addr(&addr)) {
                ast_verbose("Got  RTP packet from    %s (type %-2.2d, seq %-6.6u, ts %-6.6u, len %-6.6d)\n",
                            ast_sockaddr_stringify(&addr),
@@ -9088,11 +9204,145 @@ static char *handle_cli_rtcp_set_stats(struct ast_cli_entry *e, int cmd, struct
        return CLI_SUCCESS;
 }
 
+#ifdef AST_DEVMODE
+
+static unsigned int use_random(struct ast_cli_args *a, int pos, unsigned int index)
+{
+       return pos >= index && !ast_strlen_zero(a->argv[index - 1]) &&
+               !strcasecmp(a->argv[index - 1], "random");
+}
+
+static char *handle_cli_rtp_drop_incoming_packets(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
+{
+       static const char * const completions_2[] = { "stop", "<N>", NULL };
+       static const char * const completions_3[] = { "random", "incoming packets", NULL };
+       static const char * const completions_5[] = { "on", "every", NULL };
+       static const char * const completions_units[] = { "random", "usec", "msec", "sec", "min", NULL };
+
+       unsigned int use_random_num = 0;
+       unsigned int use_random_interval = 0;
+       unsigned int num_to_drop = 0;
+       unsigned int interval = 0;
+       const char *interval_s = NULL;
+       const char *unit_s = NULL;
+       struct ast_sockaddr addr;
+       const char *addr_s = NULL;
+
+       switch (cmd) {
+       case CLI_INIT:
+               e->command = "rtp drop";
+               e->usage =
+                       "Usage: rtp drop [stop|[<N> [random] incoming packets[ every <N> [random] {usec|msec|sec|min}][ on <ip[:port]>]]\n"
+                       "       Drop RTP incoming packets.\n";
+               return NULL;
+       case CLI_GENERATE:
+               use_random_num = use_random(a, a->pos, 4);
+               use_random_interval = use_random(a, a->pos, 8 + use_random_num) ||
+                       use_random(a, a->pos, 10 + use_random_num);
+
+               switch (a->pos - use_random_num - use_random_interval) {
+               case 2:
+                       return ast_cli_complete(a->word, completions_2, a->n);
+               case 3:
+                       return ast_cli_complete(a->word, completions_3 + use_random_num, a->n);
+               case 5:
+                       return ast_cli_complete(a->word, completions_5, a->n);
+               case 7:
+                       if (!strcasecmp(a->argv[a->pos - 2], "on")) {
+                               ast_cli_completion_add(ast_strdup("every"));
+                               break;
+                       }
+                       /* Fall through */
+               case 9:
+                       if (!strcasecmp(a->argv[a->pos - 2 - use_random_interval], "every")) {
+                               return ast_cli_complete(a->word, completions_units + use_random_interval, a->n);
+                       }
+                       break;
+               case 8:
+                       if (!strcasecmp(a->argv[a->pos - 3 - use_random_interval], "every")) {
+                               ast_cli_completion_add(ast_strdup("on"));
+                       }
+                       break;
+               }
+
+               return NULL;
+       }
+
+       if (a->argc < 3) {
+               return CLI_SHOWUSAGE;
+       }
+
+       use_random_num = use_random(a, a->argc, 4);
+       use_random_interval = use_random(a, a->argc, 8 + use_random_num) ||
+               use_random(a, a->argc, 10 + use_random_num);
+
+       if (!strcasecmp(a->argv[2], "stop")) {
+               /* rtp drop stop */
+       } else if (a->argc < 5) {
+               return CLI_SHOWUSAGE;
+       } else if (ast_str_to_uint(a->argv[2], &num_to_drop)) {
+               ast_cli(a->fd, "%s is not a valid number of packets to drop\n", a->argv[2]);
+               return CLI_FAILURE;
+       } else if (a->argc - use_random_num == 5) {
+               /* rtp drop <N> [random] incoming packets */
+       } else if (a->argc - use_random_num >= 7 && !strcasecmp(a->argv[5 + use_random_num], "on")) {
+               /* rtp drop <N> [random] incoming packets on <ip[:port]> */
+               addr_s = a->argv[6 + use_random_num];
+               if (a->argc - use_random_num - use_random_interval == 10 &&
+                               !strcasecmp(a->argv[7 + use_random_num], "every")) {
+                       /* rtp drop <N> [random] incoming packets on <ip[:port]> every <N> [random] {usec|msec|sec|min} */
+                       interval_s = a->argv[8 + use_random_num];
+                       unit_s = a->argv[9 + use_random_num + use_random_interval];
+               }
+       } else if (a->argc - use_random_num >= 8 && !strcasecmp(a->argv[5 + use_random_num], "every")) {
+               /* rtp drop <N> [random] incoming packets every <N> [random] {usec|msec|sec|min} */
+               interval_s = a->argv[6 + use_random_num];
+               unit_s = a->argv[7 + use_random_num + use_random_interval];
+               if (a->argc == 10 + use_random_num + use_random_interval &&
+                               !strcasecmp(a->argv[8 + use_random_num + use_random_interval], "on")) {
+                       /* rtp drop <N> [random] incoming packets every <N> [random] {usec|msec|sec|min} on <ip[:port]> */
+                       addr_s = a->argv[9 + use_random_num + use_random_interval];
+               }
+       } else {
+               return CLI_SHOWUSAGE;
+       }
+
+       if (a->argc - use_random_num >= 8 && !interval_s && !addr_s) {
+               return CLI_SHOWUSAGE;
+       }
+
+       if (interval_s && ast_str_to_uint(interval_s, &interval)) {
+               ast_cli(a->fd, "%s is not a valid interval number\n", interval_s);
+               return CLI_FAILURE;
+       }
+
+       memset(&addr, 0, sizeof(addr));
+       if (addr_s && !ast_sockaddr_parse(&addr, addr_s, 0)) {
+               ast_cli(a->fd, "%s is not a valid hostname[:port]\n", addr_s);
+               return CLI_FAILURE;
+       }
+
+       drop_packets_data.use_random_num = use_random_num;
+       drop_packets_data.use_random_interval = use_random_interval;
+       drop_packets_data.num_to_drop = num_to_drop;
+       drop_packets_data.interval = ast_time_create_by_unit_str(interval, unit_s);
+       ast_sockaddr_copy(&drop_packets_data.addr, &addr);
+       drop_packets_data.port = ast_sockaddr_port(&addr);
+
+       drop_packets_data_update(ast_tvnow());
+
+       return CLI_SUCCESS;
+}
+#endif
+
 static struct ast_cli_entry cli_rtp[] = {
        AST_CLI_DEFINE(handle_cli_rtp_set_debug,  "Enable/Disable RTP debugging"),
        AST_CLI_DEFINE(handle_cli_rtp_settings,   "Display RTP settings"),
        AST_CLI_DEFINE(handle_cli_rtcp_set_debug, "Enable/Disable RTCP debugging"),
        AST_CLI_DEFINE(handle_cli_rtcp_set_stats, "Enable/Disable RTCP stats"),
+#ifdef AST_DEVMODE
+       AST_CLI_DEFINE(handle_cli_rtp_drop_incoming_packets, "Drop RTP incoming packets"),
+#endif
 };
 
 static int rtp_reload(int reload, int by_external_config)