From 2a2b84aa6a83ccb20820723f1c93ef3f762eb4d3 Mon Sep 17 00:00:00 2001 Message-Id: <2a2b84aa6a83ccb20820723f1c93ef3f762eb4d3.1716284474.git.mdw@distorted.org.uk> From: Mark Wooding Date: Wed, 3 Jun 2020 20:58:08 +0100 Subject: [PATCH] lib/configuration.c, lib/uaudio-rtp.c: Allow configuring payload size. Organization: Straylight/Edgeware From: Mark Wooding This is useful in unicast (or multicast-routing?) situations where packets will traverse networks with unusually small MTU. --- doc/disorder_config.5.in | 10 ++++++++++ lib/configuration.c | 2 ++ lib/configuration.h | 10 ++++++++++ lib/uaudio-rtp.c | 19 +++++++++---------- 4 files changed, 31 insertions(+), 10 deletions(-) diff --git a/doc/disorder_config.5.in b/doc/disorder_config.5.in index e57e06a..0822669 100644 --- a/doc/disorder_config.5.in +++ b/doc/disorder_config.5.in @@ -686,6 +686,16 @@ The default value is This option is experimental, and may change or be removed in a future release. .TP +.B rtp_max_payload \fBYTES\fR +Don't send RTP packets with a UDP payload larger than +.I BYTES +(including the 12-byte RTP header). If you know that you will be transmitting +RTP over networks with an unusually low MTU size, then it is probably useful to +set this option. +.IP +This option is experimental, +and may change or be removed in a future release. +.TP .B rtp_minbuffer \fIFRAMES\fR Set .BR disorder-playrtp (1)'s diff --git a/lib/configuration.c b/lib/configuration.c index d1f14e9..a87957e 100644 --- a/lib/configuration.c +++ b/lib/configuration.c @@ -1093,6 +1093,7 @@ static const struct conf conf[] = { { C(replay_min), &type_integer, validate_non_negative }, { C(rtp_always_request), &type_boolean, validate_any }, { C(rtp_delay_threshold), &type_integer, validate_positive }, + { C(rtp_max_payload), &type_integer, validate_positive }, { C(rtp_maxbuffer), &type_integer, validate_non_negative }, { C(rtp_minbuffer), &type_integer, validate_non_negative }, { C(rtp_mode), &type_string, validate_any }, @@ -1409,6 +1410,7 @@ static struct config *config_default(void) { c->listen.af = -1; c->connect.af = -1; c->rtp_mode = xstrdup("auto"); + c->rtp_max_payload = -1; return c; } diff --git a/lib/configuration.h b/lib/configuration.h index 5c33047..2b0db52 100644 --- a/lib/configuration.h +++ b/lib/configuration.h @@ -259,6 +259,16 @@ struct config { /** @brief Whether to loop back multicast packets */ int multicast_loop; + /** @brief Maximum size of RTP payload to send + * + * This is the maximum number of bytes we pass to write(2); to determine + * actual packet sizes, add a UDP header and an IP header (and a link layer + * header if it's the link layer size you care about). + * + * Don't make this too big or arithmetic will start to overflow. + */ + long rtp_max_payload; + /** @brief Login lifetime in seconds */ long cookie_login_lifetime; diff --git a/lib/uaudio-rtp.c b/lib/uaudio-rtp.c index 8559bb2..73677d5 100644 --- a/lib/uaudio-rtp.c +++ b/lib/uaudio-rtp.c @@ -41,15 +41,8 @@ #include "timeval.h" #include "configuration.h" -/** @brief Bytes to send per network packet - * - * This is the maximum number of bytes we pass to write(2); to determine actual - * packet sizes, add a UDP header and an IP header (and a link layer header if - * it's the link layer size you care about). - * - * Don't make this too big or arithmetic will start to overflow. - */ -#define NETWORK_BYTES (1500-8/*UDP*/-40/*IP*/-8/*conservatism*/) +/** @brief Bytes to send per network packet */ +static int rtp_max_payload; /** @brief RTP payload type */ static int rtp_payload; @@ -107,6 +100,7 @@ static const char *const rtp_options[] = { "multicast-ttl", "multicast-loop", "rtp-mode", + "rtp-max-payload", NULL }; @@ -326,6 +320,9 @@ static void rtp_open(void) { rtp_mode = RTP_UNICAST; } } + rtp_max_payload = atoi(uaudio_get("rtp-max-payload", "-1")); + if(rtp_max_payload < 0) + rtp_max_payload = 1500 - 8/*UDP*/ - 40/*IP*/ - 8/*conservatism*/; /* Create the sockets */ if(rtp_mode != RTP_REQUEST) { if((rtp_fd = socket(dres->ai_family, @@ -437,7 +434,7 @@ static void rtp_start(uaudio_callback *callback, userdata, rtp_play, 256 / uaudio_sample_size, - (NETWORK_BYTES - sizeof(struct rtp_header)) + (rtp_max_payload - sizeof(struct rtp_header)) / uaudio_sample_size, 0); if(config->rtp_verbose) @@ -464,6 +461,8 @@ static void rtp_configure(void) { snprintf(buffer, sizeof buffer, "%ld", config->multicast_ttl); uaudio_set("multicast-ttl", buffer); uaudio_set("multicast-loop", config->multicast_loop ? "yes" : "no"); + snprintf(buffer, sizeof buffer, "%ld", config->rtp_max_payload); + uaudio_set("rtp-max-payload", buffer); if(config->rtp_verbose) disorder_info("RTP: configured"); } -- [mdw]