[pulseaudio-discuss] [PATCH 4/8] rtp: Move MTU handling to the RTP implementation

[arun at accosted.net]

From: Arun Raghavan <git at arunraghavan.net>

module-rtp-send itself doesn't really need to handle this, the
implementation can keep track (and make sure sending happens in MTU
sized chunks).
---
 src/modules/rtp/module-rtp-send.c |  7 ++-----
 src/modules/rtp/rtp.c             | 14 +++++++-------
 src/modules/rtp/rtp.h             |  5 +++--
 3 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/src/modules/rtp/module-rtp-send.c b/src/modules/rtp/module-rtp-send.c
index 1c1ebea..c82adc5 100644
--- a/src/modules/rtp/module-rtp-send.c
+++ b/src/modules/rtp/module-rtp-send.c
@@ -109,7 +109,6 @@ struct userdata {
 
     pa_rtp_context rtp_context;
     pa_sap_context sap_context;
-    size_t mtu;
 
     pa_time_event *sap_event;
 
@@ -144,7 +143,7 @@ static void source_output_push_cb(pa_source_output *o, const pa_memchunk *chunk)
         return;
     }
 
-    pa_rtp_send(&u->rtp_context, u->mtu, u->memblockq);
+    pa_rtp_send(&u->rtp_context, u->memblockq);
 }
 
 static pa_source_output_flags_t get_dont_inhibit_auto_suspend_flag(pa_source *source,
@@ -466,8 +465,6 @@ int pa__init(pa_module*m) {
             0,
             NULL);
 
-    u->mtu = mtu;
-
     k = sizeof(sa_dst);
     pa_assert_se((r = getsockname(fd, (struct sockaddr*) &sa_dst, &k)) >= 0);
 
@@ -489,7 +486,7 @@ int pa__init(pa_module*m) {
 
     pa_xfree(n);
 
-    if (!pa_rtp_context_init_send(&u->rtp_context, fd, payload, pa_frame_size(&ss)))
+    if (!pa_rtp_context_init_send(&u->rtp_context, fd, payload, mtu, pa_frame_size(&ss)))
         goto fail;
     pa_sap_context_init_send(&u->sap_context, sap_fd, p);
 
diff --git a/src/modules/rtp/rtp.c b/src/modules/rtp/rtp.c
index a5a5082..8da658a 100644
--- a/src/modules/rtp/rtp.c
+++ b/src/modules/rtp/rtp.c
@@ -43,7 +43,7 @@
 
 #include "rtp.h"
 
-bool pa_rtp_context_init_send(pa_rtp_context *c, int fd, uint8_t payload, size_t frame_size) {
+bool pa_rtp_context_init_send(pa_rtp_context *c, int fd, uint8_t payload, size_t mtu, size_t frame_size) {
     pa_assert(c);
     pa_assert(fd >= 0);
 
@@ -53,6 +53,7 @@ bool pa_rtp_context_init_send(pa_rtp_context *c, int fd, uint8_t payload, size_t
     c->ssrc = (uint32_t) (rand()*rand());
     c->payload = (uint8_t) (payload & 127U);
     c->frame_size = frame_size;
+    c->mtu = mtu;
 
     pa_memchunk_reset(&c->memchunk);
 
@@ -61,17 +62,16 @@ bool pa_rtp_context_init_send(pa_rtp_context *c, int fd, uint8_t payload, size_t
 
 #define MAX_IOVECS 16
 
-int pa_rtp_send(pa_rtp_context *c, size_t size, pa_memblockq *q) {
+int pa_rtp_send(pa_rtp_context *c, pa_memblockq *q) {
     struct iovec iov[MAX_IOVECS];
     pa_memblock* mb[MAX_IOVECS];
     int iov_idx = 1;
     size_t n = 0;
 
     pa_assert(c);
-    pa_assert(size > 0);
     pa_assert(q);
 
-    if (pa_memblockq_get_length(q) < size)
+    if (pa_memblockq_get_length(q) < c->mtu)
         return 0;
 
     for (;;) {
@@ -82,7 +82,7 @@ int pa_rtp_send(pa_rtp_context *c, size_t size, pa_memblockq *q) {
 
         if ((r = pa_memblockq_peek(q, &chunk)) >= 0) {
 
-            size_t k = n + chunk.length > size ? size - n : chunk.length;
+            size_t k = n + chunk.length > c->mtu ? c->mtu - n : chunk.length;
 
             pa_assert(chunk.memblock);
 
@@ -97,7 +97,7 @@ int pa_rtp_send(pa_rtp_context *c, size_t size, pa_memblockq *q) {
 
         pa_assert(n % c->frame_size == 0);
 
-        if (r < 0 || n >= size || iov_idx >= MAX_IOVECS) {
+        if (r < 0 || n >= c->mtu || iov_idx >= MAX_IOVECS) {
             uint32_t header[3];
             struct msghdr m;
             ssize_t k;
@@ -138,7 +138,7 @@ int pa_rtp_send(pa_rtp_context *c, size_t size, pa_memblockq *q) {
                 return -1;
             }
 
-            if (r < 0 || pa_memblockq_get_length(q) < size)
+            if (r < 0 || pa_memblockq_get_length(q) < c->mtu)
                 break;
 
             n = 0;
diff --git a/src/modules/rtp/rtp.h b/src/modules/rtp/rtp.h
index 57be3e4..350f968 100644
--- a/src/modules/rtp/rtp.h
+++ b/src/modules/rtp/rtp.h
@@ -33,15 +33,16 @@ typedef struct pa_rtp_context {
     uint32_t ssrc;
     uint8_t payload;
     size_t frame_size;
+    size_t mtu;
 
     pa_memchunk memchunk;
 } pa_rtp_context;
 
-bool pa_rtp_context_init_send(pa_rtp_context *c, int fd, uint8_t payload, size_t frame_size);
+bool pa_rtp_context_init_send(pa_rtp_context *c, int fd, uint8_t payload, size_t mtu, size_t frame_size);
 
 /* If the memblockq doesn't have a silence memchunk set, then the caller must
  * guarantee that the current read index doesn't point to a hole. */
-int pa_rtp_send(pa_rtp_context *c, size_t size, pa_memblockq *q);
+int pa_rtp_send(pa_rtp_context *c, pa_memblockq *q);
 
 pa_rtp_context* pa_rtp_context_init_recv(pa_rtp_context *c, int fd, size_t frame_size);
 int pa_rtp_recv(pa_rtp_context *c, pa_memchunk *chunk, pa_mempool *pool, struct timeval *tstamp);
-- 
2.5.0