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Improved UDP socket binding, multicast and IPv6

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This commit is contained in:
Thulinma 2016-09-22 09:31:30 +02:00
parent 29c37fd4e9
commit 3639705ef6
2 changed files with 193 additions and 75 deletions
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255
lib/socket.cpp
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@ -371,10 +371,6 @@ Socket::Connection::Connection(std::string host, int port, bool nonblock) {
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_flags = AI_ADDRCONFIG;
hints.ai_protocol = 0;
hints.ai_canonname = NULL;
hints.ai_addr = NULL;
hints.ai_next = NULL;
int s = getaddrinfo(host.c_str(), ss.str().c_str(), &hints, &result);
if (s != 0) {
DEBUG_MSG(DLVL_FAIL, "Could not connect to %s:%i! Error: %s", host.c_str(), port, gai_strerror(s));
@ -969,14 +965,14 @@ int Socket::Server::getSocket() {
Socket::UDPConnection::UDPConnection(bool nonblock) {
#ifdef __CYGWIN__
#warning UDP over IPv6 is currently disabled on windows
isIPv6 = false;
family = AF_INET;
sock = socket(AF_INET, SOCK_DGRAM, 0);
#else
isIPv6 = true;
family = AF_INET6;
sock = socket(AF_INET6, SOCK_DGRAM, 0);
if (sock == -1) {
sock = socket(AF_INET, SOCK_DGRAM, 0);
isIPv6 = false;
family = AF_INET;
}
#endif
if (sock == -1) {
@ -999,14 +995,14 @@ Socket::UDPConnection::UDPConnection(bool nonblock) {
Socket::UDPConnection::UDPConnection(const UDPConnection & o) {
#ifdef __CYGWIN__
#warning UDP over IPv6 is currently disabled on windows
isIPv6 = false;
family = AF_INET;
sock = socket(AF_INET, SOCK_DGRAM, 0);
#else
isIPv6 = true;
family = AF_INET6;
sock = socket(AF_INET6, SOCK_DGRAM, 0);
if (sock == -1) {
sock = socket(AF_INET, SOCK_DGRAM, 0);
isIPv6 = false;
family = AF_INET;
}
#endif
if (sock == -1) {
@ -1032,14 +1028,19 @@ Socket::UDPConnection::UDPConnection(const UDPConnection & o) {
data_len = 0;
}
/// Closes the UDP socket, cleans up any memory allocated by the socket.
Socket::UDPConnection::~UDPConnection() {
/// Close the UDP socket
void Socket::UDPConnection::close(){
if (sock != -1) {
errno = EINTR;
while (::close(sock) != 0 && errno == EINTR) {
}
sock = -1;
}
}
/// Closes the UDP socket, cleans up any memory allocated by the socket.
Socket::UDPConnection::~UDPConnection() {
close();
if (destAddr) {
free(destAddr);
destAddr = 0;
@ -1058,21 +1059,38 @@ void Socket::UDPConnection::SetDestination(std::string destIp, uint32_t port) {
destAddr = 0;
}
destAddr = malloc(sizeof(struct sockaddr_in6));
if (destAddr) {
if (!destAddr) {
return;
}
destAddr_size = sizeof(struct sockaddr_in6);
memset(destAddr, 0, destAddr_size);
((struct sockaddr_in6 *)destAddr)->sin6_family = AF_INET6;
((struct sockaddr_in6 *)destAddr)->sin6_port = htons(port);
if (inet_pton(AF_INET6, destIp.c_str(), &(((struct sockaddr_in6 *)destAddr)->sin6_addr)) == 1) {
struct addrinfo * result, *rp, hints;
std::stringstream ss;
ss << port;
memset(&hints, 0, sizeof(struct addrinfo));
hints.ai_family = family;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_flags = AI_ADDRCONFIG;
hints.ai_protocol = 0;
hints.ai_canonname = NULL;
hints.ai_addr = NULL;
hints.ai_next = NULL;
int s = getaddrinfo(destIp.c_str(), ss.str().c_str(), &hints, &result);
if (s != 0) {
DEBUG_MSG(DLVL_FAIL, "Could not connect UDP socket to %s:%i! Error: %s", destIp.c_str(), port, gai_strerror(s));
return;
}
memset(destAddr, 0, destAddr_size);
((struct sockaddr_in *)destAddr)->sin_family = AF_INET;
((struct sockaddr_in *)destAddr)->sin_port = htons(port);
if (inet_pton(AF_INET, destIp.c_str(), &(((struct sockaddr_in *)destAddr)->sin_addr)) == 1) {
for (rp = result; rp != NULL; rp = rp->ai_next) {
//assume success
memcpy(destAddr, rp->ai_addr, rp->ai_addrlen);
freeaddrinfo(result);
return;
//\todo Possibly detect and handle failure
}
}
freeaddrinfo(result);
free(destAddr);
destAddr = 0;
DEBUG_MSG(DLVL_FAIL, "Could not set destination for UDP socket: %s:%d", destIp.c_str(), port);
@ -1158,64 +1176,163 @@ void Socket::UDPConnection::SendNow(const char * sdata, size_t len) {
}
/// Bind to a port number, returning the bound port.
/// Attempts to bind over IPv6 first.
/// If it fails, attempts to bind over IPv4.
/// If that fails too, gives up and returns zero.
/// Prints a debug message at DLVL_FAIL level if binding failed.
/// If that fails, returns zero.
/// \arg port Port to bind to, required.
/// \arg iface Interface address to listen for packets on (may be multicast address)
/// \arg multicastInterfaces Comma-separated list of interfaces to listen on for multicast packets. Optional, left out means automatically chosen by kernel.
/// \return Actually bound port number, or zero on error.
int Socket::UDPConnection::bind(int port, std::string iface, const std::string & multicastInterfaces) {
close();//we open a new socket for each attempt
int result = 0;
if (isIPv6) {
struct sockaddr_in6 s6;
memset(&s6, 0, sizeof(s6));
s6.sin6_family = AF_INET6;
int addr_ret;
bool multicast = false;
struct addrinfo hints, *addr_result, *rp;
memset(&hints, 0, sizeof(hints));
hints.ai_flags = AI_V4MAPPED | AI_ADDRCONFIG | AI_PASSIVE;
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_protocol = IPPROTO_UDP;
std::stringstream ss;
ss << port;
if (iface == "0.0.0.0" || iface.length() == 0) {
s6.sin6_addr = in6addr_any;
} else {
inet_pton(AF_INET6, iface.c_str(), &s6.sin6_addr);
}
s6.sin6_port = htons(port);
int r = ::bind(sock, (sockaddr *)&s6, sizeof(s6));
if (r == 0) {
result = ntohs(s6.sin6_port);
}
} else {
struct sockaddr_in s4;
memset(&s4, 0, sizeof(s4));
s4.sin_family = AF_INET;
if (iface == "0.0.0.0" || iface.length() == 0) {
s4.sin_addr.s_addr = htonl(INADDR_ANY);
} else {
inet_pton(AF_INET, iface.c_str(), &s4.sin_addr);
}
s4.sin_port = htons(port);
int r = ::bind(sock, (sockaddr *)&s4, sizeof(s4));
if (r == 0) {
result = ntohs(s4.sin_port);
}
}
if (!result){
DEBUG_MSG(DLVL_FAIL, "Could not bind %s UDP socket to port %d: %s", isIPv6 ? "IPv6" : "IPv4", port, strerror(errno));
if ((addr_ret = getaddrinfo(0, ss.str().c_str(), &hints, &addr_result)) != 0){
FAIL_MSG("Could not resolve %s for UDP: %s", iface.c_str(), gai_strerror(addr_ret));
return 0;
}
//Detect multicast
if (iface.length() && ((atoi(iface.c_str()) & 0xE0) == 0xE0)){
if (!multicastInterfaces.length()){
WARN_MSG("Multicast IP given without any defined interfaces");
}else{
struct ip_mreq group;
inet_pton(AF_INET, iface.c_str(), &group.imr_multiaddr.s_addr);
size_t loc = 0;
while (loc != std::string::npos){
size_t nxtPos = multicastInterfaces.find(',', loc);
if ((addr_ret = getaddrinfo(iface.c_str(), ss.str().c_str(), &hints, &addr_result)) != 0){
FAIL_MSG("Could not resolve %s for UDP: %s", iface.c_str(), gai_strerror(addr_ret));
return 0;
}
}
std::string err_str;
for (rp = addr_result; rp != NULL; rp = rp->ai_next) {
sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
if (sock == -1) {
continue;
}
char human_addr[INET6_ADDRSTRLEN];
getnameinfo(rp->ai_addr, rp->ai_addrlen, human_addr, INET6_ADDRSTRLEN, 0, 0, NI_NUMERICHOST);
MEDIUM_MSG("Attempting bind to %s (%s)", human_addr, rp->ai_family == AF_INET6 ? "IPv6" : "IPv4");
if (::bind(sock, rp->ai_addr, rp->ai_addrlen) == 0) {
family = rp->ai_family;
hints.ai_family = family;
break;
}
if (err_str.size()){err_str += ", ";}
err_str += human_addr;
err_str += ":";
err_str += strerror(errno);
close();//we open a new socket for each attempt
}
if (sock == -1){
FAIL_MSG("Could not open %s for UDP: %s", iface.c_str(), err_str.c_str());
freeaddrinfo(addr_result);
return 0;
}
//socket is bound! Let's collect some more data...
if (family == AF_INET6){
sockaddr_in6 * addr6 = (sockaddr_in6*)(rp->ai_addr);
result = ntohs(addr6->sin6_port);
if (memcmp((char*)&(addr6->sin6_addr), "\000\000\000\000\000\000\000\000\000\000\377\377", 12) == 0){
//IPv6-mapped IPv4 address - 13th byte ([12]) holds the first IPv4 byte
multicast = (((char*)&(addr6->sin6_addr))[12] & 0xF0) == 0xE0;
}else{
//"normal" IPv6 address - prefix ff00::/8
multicast = (((char*)&(addr6->sin6_addr))[0] == 0xFF);
}
}else{
sockaddr_in * addr4 = (sockaddr_in*)(rp->ai_addr);
result = ntohs(addr4->sin_port);
//multicast has a "1110" bit prefix
multicast = (((char*)&(addr4->sin_addr))[0] & 0xF0) == 0xE0;
}
freeaddrinfo(addr_result);
//handle multicast membership(s)
if (multicast){
struct ipv6_mreq mreq6;
struct ip_mreq mreq4;
memset(&mreq4, 0, sizeof(mreq4));
memset(&mreq6, 0, sizeof(mreq6));
struct addrinfo *reslocal, *resmulti;
if ((addr_ret = getaddrinfo(iface.c_str(), 0, &hints, &resmulti)) != 0){
WARN_MSG("Unable to parse multicast address: %s", gai_strerror(addr_ret));
close();
result = -1;
return result;
}
if (!multicastInterfaces.length()){
if (family == AF_INET6){
memcpy(&mreq6.ipv6mr_multiaddr, &((sockaddr_in6*)resmulti->ai_addr)->sin6_addr, sizeof(mreq6.ipv6mr_multiaddr));
if (setsockopt(sock, IPPROTO_IPV6, IPV6_JOIN_GROUP, (char *)&mreq6, sizeof(mreq6)) != 0) {
FAIL_MSG("Unable to register for IPv6 multicast on all interfaces: %s", strerror(errno));
close();
result = -1;
}
}else{
mreq4.imr_multiaddr = ((sockaddr_in*)resmulti->ai_addr)->sin_addr;
mreq4.imr_interface.s_addr = INADDR_ANY;
if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&mreq4, sizeof(mreq4)) != 0) {
FAIL_MSG("Unable to register for IPv4 multicast on all interfaces: %s", strerror(errno));
close();
result = -1;
}
}
}else{
size_t nxtPos = std::string::npos;
bool atLeastOne = false;
for (size_t loc = 0; loc != std::string::npos; loc = (nxtPos == std::string::npos ? nxtPos : nxtPos + 1)){
nxtPos = multicastInterfaces.find(',', loc);
std::string curIface = multicastInterfaces.substr(loc, (nxtPos == std::string::npos ? nxtPos : nxtPos - loc));
inet_pton(AF_INET, curIface.c_str(), &group.imr_interface.s_addr);
if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&group, sizeof(group)) < 0) {
WARN_MSG("Unable to register for multicast on interface %s: %s", curIface.c_str() , strerror(errno));
}
loc = (nxtPos == std::string::npos ? nxtPos : nxtPos + 1);
//do a bit of filtering for IPv6, removing the []-braces, if any
if (curIface[0] == '['){
if (curIface[curIface.size() - 1] == ']'){
curIface = curIface.substr(1, curIface.size()-2);
}else{
curIface = curIface.substr(1, curIface.size()-1);
}
}
if (family == AF_INET6){
INFO_MSG("Registering for IPv6 multicast on interface %s", curIface.c_str());
if ((addr_ret = getaddrinfo(curIface.c_str(), 0, &hints, &reslocal)) != 0){
WARN_MSG("Unable to resolve IPv6 interface address %s: %s", curIface.c_str(), gai_strerror(addr_ret));
continue;
}
memcpy(&mreq6.ipv6mr_multiaddr, &((sockaddr_in6*)resmulti->ai_addr)->sin6_addr, sizeof(mreq6.ipv6mr_multiaddr));
mreq6.ipv6mr_interface = ((sockaddr_in6*)reslocal->ai_addr)->sin6_scope_id;
if (setsockopt(sock, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, (char *)&mreq6, sizeof(mreq6)) != 0) {
FAIL_MSG("Unable to register for IPv6 multicast on interface %s (%u): %s", curIface.c_str(), ((sockaddr_in6*)reslocal->ai_addr)->sin6_scope_id, strerror(errno));
}else{
atLeastOne = true;
}
}else{
INFO_MSG("Registering for IPv4 multicast on interface %s", curIface.c_str());
if ((addr_ret = getaddrinfo(curIface.c_str(), 0, &hints, &reslocal)) != 0){
WARN_MSG("Unable to resolve IPv4 interface address %s: %s", curIface.c_str(), gai_strerror(addr_ret));
continue;
}
mreq4.imr_multiaddr = ((sockaddr_in*)resmulti->ai_addr)->sin_addr;
mreq4.imr_interface = ((sockaddr_in*)reslocal->ai_addr)->sin_addr;
if (setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&mreq4, sizeof(mreq4)) != 0) {
FAIL_MSG("Unable to register for IPv4 multicast on interface %s: %s", curIface.c_str() , strerror(errno));
}else{
atLeastOne = true;
}
}
if (!atLeastOne){
close();
result = -1;
}
freeaddrinfo(reslocal);//free resolved interface addr
}//loop over all interfaces
}
freeaddrinfo(resmulti);//free resolved multicast addr
}
return result;
}

3
lib/socket.h
View file

@ -129,13 +129,14 @@ namespace Socket {
unsigned int up;///< Amount of bytes transferred up.
unsigned int down;///< Amount of bytes transferred down.
unsigned int data_size;///< The size in bytes of the allocated space in the data pointer.
bool isIPv6;//<<< True if IPv6 socket, false otherwise.
int family;///<Current socket address family
public:
char * data;///< Holds the last received packet.
unsigned int data_len; ///< The size in bytes of the last received packet.
UDPConnection(const UDPConnection & o);
UDPConnection(bool nonblock = false);
~UDPConnection();
void close();
int getSock();
int bind(int port, std::string iface = "", const std::string & multicastAddress = "");
void setBlocking(bool blocking);