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authorcbdev <cb@cbcdn.com>2020-04-11 18:40:39 +0200
committercbdev <cb@cbcdn.com>2020-04-11 18:40:39 +0200
commitb53092ac95fa25d0e6e4e4fc3de9531f43038c4f (patch)
tree8f0c94ca2aef6e1ad33ed1fe84bc18dd598ad9db
parentc52f3d7f48daaaed52277363beb8325e67d67469 (diff)
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Use local interface addresses for mDNS announce
-rw-r--r--backends/Makefile2
-rw-r--r--backends/libmmbackend.c15
-rw-r--r--backends/libmmbackend.h4
-rw-r--r--backends/rtpmidi.c218
-rw-r--r--backends/rtpmidi.h6
-rw-r--r--backends/rtpmidi.md9
6 files changed, 220 insertions, 34 deletions
diff --git a/backends/Makefile b/backends/Makefile
index c19d9dd..1e66995 100644
--- a/backends/Makefile
+++ b/backends/Makefile
@@ -48,7 +48,7 @@ maweb.dll: CFLAGS += -DMAWEB_NO_LIBSSL
rtpmidi.so: ADDITIONAL_OBJS += $(BACKEND_LIB)
rtpmidi.dll: ADDITIONAL_OBJS += $(BACKEND_LIB)
-rtpmidi.dll: LDLIBS += -lws2_32
+rtpmidi.dll: LDLIBS += -lws2_32 -liphlpapi
winmidi.dll: ADDITIONAL_OBJS += $(BACKEND_LIB)
winmidi.dll: LDLIBS += -lwinmm -lws2_32
diff --git a/backends/libmmbackend.c b/backends/libmmbackend.c
index b9513ac..ab96646 100644
--- a/backends/libmmbackend.c
+++ b/backends/libmmbackend.c
@@ -1,6 +1,21 @@
#include "libmmbackend.h"
#define LOGPF(format, ...) fprintf(stderr, "libmmbe\t" format "\n", __VA_ARGS__)
+#define LOG(message) fprintf(stderr, "libmmbe\t%s\n", (message))
+
+int mmbackend_strdup(char** dest, char* src){
+ if(*dest){
+ free(*dest);
+ }
+
+ *dest = strdup(src);
+
+ if(!*dest){
+ LOG("Failed to allocate memory");
+ return 1;
+ }
+ return 0;
+}
void mmbackend_parse_hostspec(char* spec, char** host, char** port, char** options){
size_t u = 0;
diff --git a/backends/libmmbackend.h b/backends/libmmbackend.h
index aa0d0f0..cb211a6 100644
--- a/backends/libmmbackend.h
+++ b/backends/libmmbackend.h
@@ -18,6 +18,10 @@
/*** BACKEND IMPLEMENTATION LIBRARY ***/
+/** Convenience functions **/
+
+int mmbackend_strdup(char** dest, char* src);
+
/** Networking functions **/
/*
diff --git a/backends/rtpmidi.c b/backends/rtpmidi.c
index 9d84cde..95a50d2 100644
--- a/backends/rtpmidi.c
+++ b/backends/rtpmidi.c
@@ -7,9 +7,19 @@
#include <fcntl.h>
#include <ctype.h>
+//mmbackend pulls in windows.h, required before more specific includes
#include "libmmbackend.h"
#include "rtpmidi.h"
+#ifdef _WIN32
+#include <iphlpapi.h>
+#else
+#include <arpa/inet.h>
+#include <sys/types.h>
+#include <ifaddrs.h>
+#endif
+
+
//#include "../tests/hexdump.c"
//TODO learn peer ssrcs
@@ -17,7 +27,9 @@
//TODO internal loop mode
//TODO announce on mdns input
//TODO connect to discovered peers
-//TODO push correct addresses to discovery
+//TODO refactor cfg.announces
+//TODO windows address discovery
+//TODO for some reason, the announce packet generates an exception in the wireshark dissector
static struct /*_rtpmidi_global*/ {
int mdns_fd;
@@ -25,6 +37,10 @@ static struct /*_rtpmidi_global*/ {
uint8_t detect;
uint64_t last_service;
+ char* mdns_interface;
+ size_t addresses;
+ rtpmidi_addr* address;
+
size_t announces;
rtpmidi_announce* announce;
} cfg = {
@@ -217,6 +233,137 @@ bail:
return -1;
}
+#ifdef _WIN32
+static int rtpmidi_wide_pfxcmp(wchar_t* haystack, char* needle){
+ size_t u;
+
+ for(u = 0; haystack[u] && needle[u]; u++){
+ if(haystack[u] != needle[u]){
+ return 1;
+ }
+ }
+
+ if(!haystack[u] && needle[u]){
+ return 1;
+ }
+ return 0;
+}
+
+//this has become available with vista for some reason...
+static char* inet_ntop(int family, uint8_t* data, char* buffer, size_t length){
+ switch(family){
+ case AF_INET:
+ snprintf(buffer, length, "%d.%d.%d.%d", data[0], data[1], data[2], data[3]);
+ break;
+ case AF_INET6:
+ snprintf(buffer, length, "%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X",
+ data[0], data[1], data[2], data[3],
+ data[4], data[5], data[6], data[7],
+ data[8], data[9], data[10], data[11],
+ data[12], data[13], data[14], data[15]);
+ break;
+ }
+ return buffer;
+}
+#endif
+
+static int rtpmidi_announce_addrs(){
+ char repr[INET6_ADDRSTRLEN + 1];
+ union {
+ struct sockaddr_in* in4;
+ struct sockaddr_in6* in6;
+ struct sockaddr* in;
+ } addr;
+
+ #ifdef _WIN32
+ size_t bytes_alloc = 50 * sizeof(IP_ADAPTER_ADDRESSES);
+ IP_ADAPTER_UNICAST_ADDRESS_LH* unicast_addr = NULL;
+ IP_ADAPTER_ADDRESSES* addrs = calloc(1, bytes_alloc), *iter = NULL;
+ if(!addrs){
+ LOG("Failed to allocate memory");
+ return 1;
+ }
+
+ if(GetAdaptersAddresses(0, GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST | GAA_FLAG_SKIP_DNS_SERVER,
+ NULL, addrs, (unsigned long*) &bytes_alloc) != ERROR_SUCCESS){
+ //FIXME might try to resize the result list and retry at some point...
+ LOG("Failed to query local interface addresses");
+ free(addrs);
+ return 1;
+ }
+
+ for(iter = addrs; iter; iter = iter->Next){
+ //filter interfaces if requested
+ if(cfg.mdns_interface && rtpmidi_wide_pfxcmp(iter->FriendlyName, cfg.mdns_interface)){
+ continue;
+ }
+
+ for(unicast_addr = (IP_ADAPTER_UNICAST_ADDRESS_LH*) iter->FirstUnicastAddress; unicast_addr; unicast_addr = unicast_addr->Next){
+ addr.in = unicast_addr->Address.lpSockaddr;
+ if(addr.in->sa_family != AF_INET && addr.in->sa_family != AF_INET6){
+ continue;
+ }
+
+ cfg.address = realloc(cfg.address, (cfg.addresses + 1) * sizeof(rtpmidi_addr));
+ if(!cfg.address){
+ cfg.addresses = 0;
+ LOG("Failed to allocate memory");
+ return 1;
+ }
+
+ cfg.address[cfg.addresses].family = addr.in->sa_family;
+ memcpy(&cfg.address[cfg.addresses].addr,
+ (addr.in->sa_family == AF_INET) ? (void*) &addr.in4->sin_addr.s_addr : (void*) &addr.in6->sin6_addr.s6_addr,
+ (addr.in->sa_family == AF_INET) ? 4 : 16);
+ LOGPF("mDNS announce address %" PRIsize_t ": %s (from %S)", cfg.addresses, inet_ntop(addr.in->sa_family, cfg.address[cfg.addresses].addr, repr, sizeof(repr)), iter->FriendlyName);
+ cfg.addresses++;
+ }
+ }
+
+ free(addrs);
+ #else
+ struct ifaddrs* ifa = NULL, *iter = NULL;
+
+ if(getifaddrs(&ifa)){
+ LOGPF("Failed to get adapter address information: %s", strerror(errno));
+ return 1;
+ }
+
+ for(iter = ifa; iter; iter = iter->ifa_next){
+ if((!cfg.mdns_interface || !strcmp(cfg.mdns_interface, iter->ifa_name))
+ && strcmp(iter->ifa_name, "lo")
+ && iter->ifa_addr){
+ addr.in = iter->ifa_addr;
+ if(addr.in->sa_family != AF_INET && addr.in->sa_family != AF_INET6){
+ continue;
+ }
+
+ cfg.address = realloc(cfg.address, (cfg.addresses + 1) * sizeof(rtpmidi_addr));
+ if(!cfg.address){
+ cfg.addresses = 0;
+ LOG("Failed to allocate memory");
+ return 1;
+ }
+
+ cfg.address[cfg.addresses].family = addr.in->sa_family;
+ memcpy(&cfg.address[cfg.addresses].addr,
+ (addr.in->sa_family == AF_INET) ? (void*) &addr.in4->sin_addr.s_addr : (void*) &addr.in6->sin6_addr.s6_addr,
+ (addr.in->sa_family == AF_INET) ? 4 : 16);
+ LOGPF("mDNS announce address %" PRIsize_t ": %s (from %s)", cfg.addresses, inet_ntop(addr.in->sa_family, cfg.address[cfg.addresses].addr, repr, sizeof(repr)), iter->ifa_name);
+ cfg.addresses++;
+ }
+ }
+
+ freeifaddrs(ifa);
+ #endif
+
+ if(!cfg.addresses){
+ LOG("Failed to gather local IP addresses for mDNS announce");
+ return 1;
+ }
+ return 0;
+}
+
static uint32_t rtpmidi_interval(){
return max(0, RTPMIDI_SERVICE_INTERVAL - (mm_timestamp() - cfg.last_service));
}
@@ -228,12 +375,15 @@ static int rtpmidi_configure(char* option, char* value){
return 1;
}
- cfg.mdns_name = strdup(value);
- if(!cfg.mdns_name){
- LOG("Failed to allocate memory");
+ return mmbackend_strdup(&cfg.mdns_name, value);
+ }
+ else if(!strcmp(option, "mdns-interface")){
+ if(cfg.mdns_interface){
+ LOG("Duplicate mdns-interface assignment");
return 1;
}
- return 0;
+
+ return mmbackend_strdup(&cfg.mdns_interface, value);
}
else if(!strcmp(option, "detect")){
cfg.detect = 0;
@@ -474,13 +624,7 @@ static int rtpmidi_configure_instance(instance* inst, char* option, char* value)
LOGPF("Invalid instance title %s on %s: Must be shorter than 254 characters, no periods", value, inst->name);
return 1;
}
- free(data->title);
- data->title = strdup(value);
- if(!data->title){
- LOG("Failed to allocate memory");
- return 1;
- }
- return 0;
+ return mmbackend_strdup(&data->title, value);
}
else if(!strcmp(option, "invite")){
if(data->mode != apple){
@@ -495,13 +639,7 @@ static int rtpmidi_configure_instance(instance* inst, char* option, char* value)
LOG("'join' option is only valid for apple mode instances");
return 1;
}
- free(data->accept);
- data->accept = strdup(value);
- if(!data->accept){
- LOG("Failed to allocate memory");
- return 1;
- }
- return 0;
+ return mmbackend_strdup(&data->accept, value);
}
LOGPF("Unknown instance configuration option %s on instance %s", option, inst->name);
@@ -1069,6 +1207,7 @@ bail:
return 1;
}
+//FIXME this should not exceed 1500 bytes
static int rtpmidi_mdns_announce(rtpmidi_instance_data* data){
uint8_t frame[RTPMIDI_PACKET_BUFFER] = "";
dns_header* hdr = (dns_header*) frame;
@@ -1077,7 +1216,7 @@ static int rtpmidi_mdns_announce(rtpmidi_instance_data* data){
dns_name name = {
.alloc = 0
};
- size_t offset = 0;
+ size_t offset = 0, host_offset = 0, u = 0;
ssize_t bytes = 0;
hdr->id = 0;
@@ -1085,7 +1224,7 @@ static int rtpmidi_mdns_announce(rtpmidi_instance_data* data){
hdr->flags[1] = 0;
hdr->questions = hdr->servers = 0;
hdr->answers = htobe16(4);
- hdr->additional = htobe16(1);
+ hdr->additional = htobe16(cfg.addresses);
offset = sizeof(dns_header);
//answer 1: SRV FQDN
@@ -1150,19 +1289,35 @@ static int rtpmidi_mdns_announce(rtpmidi_instance_data* data){
frame[offset++] = 0xC0;
frame[offset++] = sizeof(dns_header);
- //additional 1: A host
+ //additional 1: first announce addr
+ host_offset = offset;
snprintf((char*) frame + offset, sizeof(frame) - offset, "%s.local", cfg.mdns_name);
- bytes = dns_push_rr(frame + offset, sizeof(frame) - offset, &rr, (char*) frame + offset, 1, 1, 120, 4);
+ bytes = dns_push_rr(frame + offset, sizeof(frame) - offset, &rr, (char*) frame + offset,
+ (cfg.address[0].family == AF_INET) ? 1 : 28, 1, 120,
+ (cfg.address[0].family == AF_INET) ? 4 : 16);
if(bytes < 0){
return 1;
}
offset += bytes;
- //TODO get local addresses here
- frame[offset++] = 0x0A;
- frame[offset++] = 0x17;
- frame[offset++] = 0x01;
- frame[offset++] = 0x07;
+ memcpy(frame + offset, cfg.address[0].addr, (cfg.address[0].family == AF_INET) ? 4 : 16);
+ offset += (cfg.address[0].family == AF_INET) ? 4 : 16;
+
+ //push all other announce addresses with a pointer
+ for(u = 1; u < cfg.addresses; u++){
+ frame[offset++] = 0xC0 | (host_offset >> 8);
+ frame[offset++] = host_offset & 0xFF;
+ bytes = dns_push_rr(frame + offset, sizeof(frame) - offset, &rr, (char*) frame + offset,
+ (cfg.address[u].family == AF_INET) ? 1 : 28, 1, 120,
+ (cfg.address[u].family == AF_INET) ? 4 : 16);
+ if(bytes < 0){
+ return 1;
+ }
+ offset += bytes;
+
+ memcpy(frame + offset, cfg.address[u].addr, (cfg.address[u].family == AF_INET) ? 4 : 16);
+ offset += (cfg.address[u].family == AF_INET) ? 4 : 16;
+ }
data->last_announce = mm_timestamp();
free(name.name);
@@ -1475,7 +1630,7 @@ static int rtpmidi_start(size_t n, instance** inst){
fds += (data->control_fd >= 0) ? 2 : 1;
}
- if(mdns_required && rtpmidi_start_mdns()){
+ if(mdns_required && (rtpmidi_announce_addrs() || rtpmidi_start_mdns())){
return 1;
}
else if(mdns_required){
@@ -1529,8 +1684,13 @@ static int rtpmidi_shutdown(size_t n, instance** inst){
cfg.announce = NULL;
cfg.announces = 0;
+ free(cfg.address);
+ cfg.addresses = 0;
+
free(cfg.mdns_name);
cfg.mdns_name = NULL;
+ free(cfg.mdns_interface);
+ cfg.mdns_interface = NULL;
if(cfg.mdns_fd >= 0){
close(cfg.mdns_fd);
}
diff --git a/backends/rtpmidi.h b/backends/rtpmidi.h
index 631c45a..9d2c40a 100644
--- a/backends/rtpmidi.h
+++ b/backends/rtpmidi.h
@@ -92,6 +92,12 @@ typedef struct /*rtpmidi_announced_instance*/ {
char** invite;
} rtpmidi_announce;
+typedef struct /*_rtpmidi_addr*/ {
+ int family;
+ //this is actually a fair bit too big, but whatever
+ uint8_t addr[sizeof(struct sockaddr_storage)];
+} rtpmidi_addr;
+
enum applemidi_command {
apple_invite = 0x494E, //IN
apple_accept = 0x4F4B, //OK
diff --git a/backends/rtpmidi.md b/backends/rtpmidi.md
index 84a7cd6..d15c9b5 100644
--- a/backends/rtpmidi.md
+++ b/backends/rtpmidi.md
@@ -22,10 +22,11 @@ stream, which may lead to inconsistencies during playback.
#### Global configuration
-| Option | Example value | Default value | Description |
-|---------------|-----------------------|-----------------------|-----------------------|
-| `detect` | `on` | `off` | Output channel specifications for any events coming in on configured instances to help with configuration. |
-| `mdns-name` | `computer1` | none | mDNS hostname to announce (`<mdns-name>.local`). Apple-mode instances with `title` configuration will be announced via mDNS if set. |
+| Option | Example value | Default value | Description |
+|-----------------------|-----------------------|-----------------------|-----------------------|
+| `detect` | `on` | `off` | Output channel specifications for any events coming in on configured instances to help with configuration. |
+| `mdns-name` | `computer1` | none | mDNS hostname to announce (`<mdns-name>.local`). Apple-mode instances with `title` configuration will be announced via mDNS if set. |
+| `mdns-interface` | `wlan0` | none | Limit addresses announced via mDNS to this interface. On Windows, this is prefix-matched against the user-editable "friendly" interface name. |
#### Instance configuration