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-rw-r--r--backends/rtpmidi.c228
-rw-r--r--backends/rtpmidi.h9
2 files changed, 220 insertions, 17 deletions
diff --git a/backends/rtpmidi.c b/backends/rtpmidi.c
index 97364cf..9e0a4d4 100644
--- a/backends/rtpmidi.c
+++ b/backends/rtpmidi.c
@@ -10,6 +10,8 @@
#include "libmmbackend.h"
#include "rtpmidi.h"
+//#include "../tests/hexdump.c"
+
//TODO learn peer ssrcs
//TODO default mode?
//TODO internal loop mode
@@ -113,6 +115,10 @@ static int dns_decode_name(uint8_t* buffer, size_t len, size_t start, dns_name*
//check whether we have space in the output
if(output_offset + DNS_LABEL_LENGTH(current_label) > out->alloc){
out->name = realloc(out->name, (output_offset + DNS_LABEL_LENGTH(current_label) + 2) * sizeof(uint8_t));
+ if(!out->name){
+ LOG("Failed to allocate memory");
+ return 1;
+ }
out->alloc = output_offset + DNS_LABEL_LENGTH(current_label);
}
@@ -130,6 +136,43 @@ static int dns_decode_name(uint8_t* buffer, size_t len, size_t start, dns_name*
return 0;
}
+static int dns_encode_name(char* name, dns_name* out){
+ char* save = NULL, *token = NULL;
+ out->length = 0;
+
+ for(token = strtok_r(name, ".", &save); token; token = strtok_r(NULL, ".", &save)){
+ //make space for this label, its length and a trailing root label
+ if(out->alloc < out->length + strlen(token) + 1 + 1){
+ out->name = realloc(out->name, (out->length + strlen(token) + 2) * sizeof(char));
+ if(!out->name){
+ LOG("Failed to allocate memory");
+ return 1;
+ }
+ out->alloc = out->length + strlen(token) + 2;
+ }
+ //FIXME check label length before adding
+ out->name[out->length] = strlen(token);
+ memcpy(out->name + out->length + 1, token, strlen(token));
+ out->length += strlen(token) + 1;
+ }
+
+ //last-effort allocate a root buffer
+ if(!out->alloc){
+ out->name = calloc(1, sizeof(char));
+ if(!out->name){
+ LOG("Failed to allocate memory");
+ return 1;
+ }
+ out->alloc = 1;
+ }
+
+ //add root label
+ out->name[out->length] = 0;
+ out->length++;
+
+ return 0;
+}
+
static uint32_t rtpmidi_interval(){
return max(0, RTPMIDI_SERVICE_INTERVAL - (mm_timestamp() - cfg.last_service));
}
@@ -160,7 +203,7 @@ static int rtpmidi_configure(char* option, char* value){
return 1;
}
-static int rtpmidi_bind_instance(rtpmidi_instance_data* data, char* host, char* port){
+static int rtpmidi_bind_instance(instance* inst, rtpmidi_instance_data* data, char* host, char* port){
struct sockaddr_storage sock_addr = {
0
};
@@ -173,19 +216,26 @@ static int rtpmidi_bind_instance(rtpmidi_instance_data* data, char* host, char*
return 1;
}
+ if(getsockname(data->fd, (struct sockaddr*) &sock_addr, &sock_len)){
+ LOGPF("Failed to fetch data port information: %s", strerror(errno));
+ return 1;
+ }
+
//bind control port
if(data->mode == apple){
- if(getsockname(data->fd, (struct sockaddr*) &sock_addr, &sock_len)){
- LOGPF("Failed to fetch data port information: %s", strerror(errno));
- return 1;
- }
-
- snprintf(control_port, sizeof(control_port), "%d", be16toh(((struct sockaddr_in*)&sock_addr)->sin_port) - 1);
+ data->control_port = be16toh(((struct sockaddr_in*) &sock_addr)->sin_port) - 1;
+ snprintf(control_port, sizeof(control_port), "%d", data->control_port);
data->control_fd = mmbackend_socket(host, control_port, SOCK_DGRAM, 1, 0);
if(data->control_fd < 0){
- LOGPF("Failed to bind control port %s", control_port);
+ LOGPF("Failed to bind control port %s for instance %s", control_port, inst->name);
return 1;
}
+
+ LOGPF("Apple mode instance %s listening on port %d", inst->name, data->control_port);
+ }
+ else{
+ data->control_port = be16toh(((struct sockaddr_in*)&sock_addr)->sin_port);
+ LOGPF("Direct mode instance %s listening on port %d", inst->name, data->control_port);
}
return 0;
@@ -334,7 +384,7 @@ static int rtpmidi_configure_instance(instance* inst, char* option, char* value)
return 1;
}
- return rtpmidi_bind_instance(data, host, port);
+ return rtpmidi_bind_instance(inst, data, host, port);
}
else if(!strcmp(option, "learn")){
if(data->mode != direct){
@@ -643,6 +693,7 @@ static int rtpmidi_handle_applemidi(instance* inst, int fd, uint8_t* frame, size
}
else if(command->command == apple_reject){
//just ignore this for now and retry the invitation
+ LOGPF("Invitation rejected on instance %s", inst->name);
}
else if(command->command == apple_leave){
//remove peer from list - this comes in on the control port, but we need to remove the data port...
@@ -910,6 +961,144 @@ static int rtpmidi_handle_control(instance* inst){
return 0;
}
+int rtpmidi_mdns_announce(rtpmidi_instance_data* data){
+ uint8_t frame[RTPMIDI_PACKET_BUFFER] = "";
+ dns_header* hdr = (dns_header*) frame;
+ dns_rr* rr = NULL;
+ dns_rr_srv* srv = NULL;
+ dns_name name = {
+ .alloc = 0
+ };
+ size_t offset = 0;
+ struct sockaddr_in mcast = {
+ .sin_family = AF_INET,
+ .sin_port = htobe16(5353),
+ .sin_addr.s_addr = htobe32(((uint32_t) 0xe00000fb))
+ };
+ struct sockaddr_in6 mcast6 = {
+ .sin6_family = AF_INET6,
+ .sin6_port = htobe16(5353),
+ .sin6_addr.s6_addr = {0xff, 0x02, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0xfb}
+ };
+
+ hdr->id = 0;
+ hdr->flags[0] = 0x84;
+ hdr->flags[1] = 0;
+ hdr->questions = hdr->servers = 0;
+ hdr->answers = htobe16(4);
+ hdr->additional = htobe16(1);
+ offset = sizeof(dns_header);
+
+ //answer 1: SRV FQDN
+ snprintf((char*) frame + offset, sizeof(frame) - offset, "%s.%s", data->session_name, RTPMIDI_MDNS_DOMAIN);
+ if(dns_encode_name((char*) frame + offset, &name)){
+ LOGPF("Failed to encode name for %s", frame);
+ return 1;
+ }
+
+ memcpy(frame + offset, name.name, name.length);
+ offset += name.length;
+
+ rr = (dns_rr*) (frame + offset);
+ rr->rtype = htobe16(33); //SRV RR
+ rr->rclass = htobe16(1); //INADDR
+ rr->ttl = htobe32(120);
+ offset += sizeof(dns_rr);
+
+ srv = (dns_rr_srv*) (frame + offset);
+ srv->priority = 0;
+ srv->weight = 0;
+ srv->port = htobe16(data->control_port);
+ offset += sizeof(dns_rr_srv);
+
+ snprintf((char*) frame + offset, sizeof(frame) - offset, "%s.local", cfg.mdns_name);
+ if(dns_encode_name((char*) frame + offset, &name)){
+ LOGPF("Failed to encode name for %s", frame + offset);
+ return 1;
+ }
+ memcpy(frame + offset, name.name, name.length);
+ offset += name.length;
+ rr->data = htobe16(sizeof(dns_rr_srv) + name.length);
+
+ //answer 2: empty TXT (apple asks for it otherwise)
+ frame[offset++] = 0xC0;
+ frame[offset++] = sizeof(dns_header);
+ rr = (dns_rr*) (frame + offset);
+ rr->rtype = htobe16(16); //TXT RR
+ rr->rclass = htobe16(1); //INADDR
+ rr->ttl = htobe32(4500);
+ rr->data = htobe16(1);
+ offset += sizeof(dns_rr);
+ frame[offset++] = 0x00; //zero-length TXT
+
+ //answer 3: dns-sd PTR _applemidi
+ snprintf((char*) frame + offset, sizeof(frame) - offset, "%s", RTPMIDI_DNSSD_DOMAIN);
+ if(dns_encode_name((char*) frame + offset, &name)){
+ LOGPF("Failed to encode name for %s", frame + offset);
+ return 1;
+ }
+ memcpy(frame + offset, name.name, name.length);
+ offset += name.length;
+
+ rr = (dns_rr*) (frame + offset);
+ rr->rtype = htobe16(12); //PTR RR
+ rr->rclass = htobe16(1); //INADDR
+ rr->ttl = htobe32(4500);
+ rr->data = htobe16(2);
+ offset += sizeof(dns_rr);
+
+ //add backref for PTR
+ frame[offset++] = 0xC0;
+ frame[offset++] = sizeof(dns_header) + frame[sizeof(dns_header)] + 1;
+
+ //answer 4: _applemidi PTR FQDN
+ frame[offset++] = 0xC0;
+ frame[offset++] = sizeof(dns_header) + frame[sizeof(dns_header)] + 1;
+
+ rr = (dns_rr*) (frame + offset);
+ rr->rtype = htobe16(12); //PTR RR
+ rr->rclass = htobe16(1); //INADDR
+ rr->ttl = htobe32(4500);
+ rr->data = htobe16(2);
+ offset += sizeof(dns_rr);
+
+ //add backref for PTR
+ frame[offset++] = 0xC0;
+ frame[offset++] = sizeof(dns_header);
+
+ //additional 1: A host
+ snprintf((char*) frame + offset, sizeof(frame) - offset, "%s.local", cfg.mdns_name);
+ if(dns_encode_name((char*) frame + offset, &name)){
+ LOGPF("Failed to encode name for %s", frame + offset);
+ return 1;
+ }
+ memcpy(frame + offset, name.name, name.length);
+ offset += name.length;
+
+ rr = (dns_rr*) (frame + offset);
+ rr->rtype = htobe16(1); //A RR
+ rr->rclass = htobe16(1); //INADDR
+ rr->ttl = htobe32(120);
+ rr->data = htobe16(4);
+ offset += sizeof(dns_rr);
+
+ //TODO get local addresses here
+ frame[offset++] = 0x0A;
+ frame[offset++] = 0x17;
+ frame[offset++] = 0x01;
+ frame[offset++] = 0x07;
+
+ //send to ipv4 and ipv6 mcasts
+ sendto(cfg.mdns_fd, frame, offset, 0, (struct sockaddr*) &mcast6, sizeof(mcast6));
+ sendto(cfg.mdns_fd, frame, offset, 0, (struct sockaddr*) &mcast, sizeof(mcast));
+
+ free(name.name);
+ return 0;
+}
+
static int rtpmidi_service(){
size_t n, u, p;
instance** inst = NULL;
@@ -938,15 +1127,16 @@ static int rtpmidi_service(){
return 1;
}
- //mdns discovery
- if(cfg.mdns_fd >= 0){
- //TODO send applemidi discovery packets
- }
for(u = 0; u < n; u++){
data = (rtpmidi_instance_data*) inst[u]->impl;
if(data->mode == apple){
+ //mdns discovery
+ if(cfg.mdns_fd >= 0){
+ rtpmidi_mdns_announce(data);
+ }
+
for(p = 0; p < data->peers; p++){
if(data->peer[p].active && data->peer[p].connected){
//apple sync
@@ -986,7 +1176,7 @@ static int rtpmidi_handle_mdns(){
.alloc = 0
};
ssize_t bytes = 0;
- size_t u = 0, offset = sizeof(dns_header);
+ size_t u = 0, offset = 0;
for(bytes = recv(cfg.mdns_fd, buffer, sizeof(buffer), 0); bytes > 0; bytes = recv(cfg.mdns_fd, buffer, sizeof(buffer), 0)){
if(bytes < sizeof(dns_header)){
@@ -1000,14 +1190,18 @@ static int rtpmidi_handle_mdns(){
hdr->servers = be16toh(hdr->servers);
hdr->additional = be16toh(hdr->additional);
+ //rfc6762 18.3: opcode != 0 -> ignore
+ //rfc6762 18.11: response code != 0 -> ignore
+
//TODO Check for ._apple-midi._udp.local.
+ offset = sizeof(dns_header);
LOGPF("ID %d, Opcode %d, %s, %d questions, %d answers, %d servers, %d additional", hdr->id, DNS_OPCODE(hdr->flags[0]), DNS_RESPONSE(hdr->flags[0]) ? "response" : "query", hdr->questions, hdr->answers, hdr->servers, hdr->additional);
for(u = 0; u < hdr->questions; u++){
dns_decode_name(buffer, bytes, offset, &name);
offset += name.length;
offset += sizeof(dns_question);
- LOGPF("Question: %s", name.name);
+ LOGPF("Question (%d bytes): %s", name.length, name.name);
}
for(u = 0; u < hdr->answers; u++){
@@ -1151,7 +1345,7 @@ static int rtpmidi_start(size_t n, instance** inst){
}
//if not bound, bind to default
- if(data->fd < 0 && rtpmidi_bind_instance(data, RTPMIDI_DEFAULT_HOST, NULL)){
+ if(data->fd < 0 && rtpmidi_bind_instance(inst[u], data, RTPMIDI_DEFAULT_HOST, NULL)){
LOGPF("Failed to bind default sockets for instance %s", inst[u]->name);
return 1;
}
@@ -1178,7 +1372,7 @@ static int rtpmidi_start(size_t n, instance** inst){
if(mdns_required && rtpmidi_start_mdns()){
return 1;
}
- else{
+ else if(mdns_required){
fds++;
}
diff --git a/backends/rtpmidi.h b/backends/rtpmidi.h
index b1fe26a..f55b543 100644
--- a/backends/rtpmidi.h
+++ b/backends/rtpmidi.h
@@ -22,6 +22,8 @@ static int rtpmidi_shutdown(size_t n, instance** inst);
#define RTPMIDI_GET_TYPE(a) ((a) & 0x7F)
#define RTPMIDI_DEFAULT_NAME "MIDIMonster"
#define RTPMIDI_SERVICE_INTERVAL 1000
+#define RTPMIDI_MDNS_DOMAIN "_apple-midi._udp.local"
+#define RTPMIDI_DNSSD_DOMAIN "_services._dns-sd._udp.local"
#define DNS_POINTER(a) (((a) & 0xC0) == 0xC0)
#define DNS_LABEL_LENGTH(a) ((a) & 0x3F)
@@ -67,6 +69,7 @@ typedef struct /*_rtmidi_instance_data*/ {
int fd;
int control_fd;
+ uint16_t control_port; /*convenience member set by rtpmidi_bind_instance*/
size_t peers;
rtpmidi_peer* peer;
@@ -161,4 +164,10 @@ typedef struct /*_dns_rr*/ {
uint32_t ttl;
uint16_t data;
} dns_rr;
+
+typedef struct /*_dns_rr_srv*/ {
+ uint16_t priority;
+ uint16_t weight;
+ uint16_t port;
+} dns_rr_srv;
#pragma pack(pop)
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-31 20:57:58 +0000