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#include <netinet/in.h>
#include <sys/socket.h>
#include <unistd.h>
#include <arpa/inet.h>
- (void)broadCast
{
int socketSD = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (socketSD <= 0) {
NSLog(@"Error: Could not open socket.");
return;
}
// set socket options enable broadcast
int broadcastEnable = 1;
int ret = setsockopt(socketSD, SOL_SOCKET, SO_BROADCAST, &broadcastEnable, sizeof(broadcastEnable));
if (ret) {
NSLog(@"Error: Could not open set socket to broadcast mode");
close(socketSD);
return;
}
// Configure the port and ip we want to send to
struct sockaddr_in broadcastAddr;
memset(&broadcastAddr, 0, sizeof(broadcastAddr));
broadcastAddr.sin_family = AF_INET;
inet_pton(AF_INET, "255.255.255.255", &broadcastAddr.sin_addr);
broadcastAddr.sin_port = htons(8585);
char *request = "message from ios by c";
ret = sendto(socketSD, request, strlen(request), 0, (struct sockaddr*)&broadcastAddr, sizeof(broadcastAddr));
if (ret < 0) {
NSLog(@"Error: Could not open send broadcast.");
close(socketSD);
return;
}
close(socketSD);
dispatch_async(dispatch_get_global_queue(0, 0), ^{
[self listenForPackets];
});
[_connectionSpinner show:YES];
[_connectionTimer invalidate];
_connectionTimer = [NSTimer scheduledTimerWithTimeInterval:3.0f target:self selector:@selector(checkConnection) userInfo:nil repeats:NO];
}
- (void)listenForPackets
{
int listeningSocket = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (listeningSocket <= 0) {
NSLog(@"Error: listenForPackets - socket() failed.");
return;
}
// set timeout to 2 seconds.
struct timeval timeV;
timeV.tv_sec = 2;
timeV.tv_usec = 0;
if (setsockopt(listeningSocket, SOL_SOCKET, SO_RCVTIMEO, &timeV, sizeof(timeV)) == -1) {
NSLog(@"Error: listenForPackets - setsockopt failed");
close(listeningSocket);
return;
}
// bind the port
struct sockaddr_in sockaddr;
memset(&sockaddr, 0, sizeof(sockaddr));
sockaddr.sin_len = sizeof(sockaddr);
sockaddr.sin_family = AF_INET;
sockaddr.sin_port = htons(18686);
sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);
int status = bind(listeningSocket, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
if (status == -1) {
close(listeningSocket);
NSLog(@"Error: listenForPackets - bind() failed.");
return;
}
// receive
struct sockaddr_in receiveSockaddr;
socklen_t receiveSockaddrLen = sizeof(receiveSockaddr);
size_t bufSize = 9216;
void *buf = malloc(bufSize);
ssize_t result = recvfrom(listeningSocket, buf, bufSize, 0, (struct sockaddr *)&receiveSockaddr, &receiveSockaddrLen);
NSData *data = nil;
if (result > 0) {
if ((size_t)result != bufSize) {
buf = realloc(buf, result);
}
data = [NSData dataWithBytesNoCopy:buf length:result freeWhenDone:YES];
char addrBuf[INET_ADDRSTRLEN];
if (inet_ntop(AF_INET, &receiveSockaddr.sin_addr, addrBuf, (size_t)sizeof(addrBuf)) == NULL) {
addrBuf[0] = '\0';
}
NSString *address = [NSString stringWithCString:addrBuf encoding:NSASCIIStringEncoding];
NSString *msg = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
dispatch_async(dispatch_get_main_queue(), ^{
[self didReceiveMessage:msg fromAddress:address];
});
} else {
free(buf);
}
close(listeningSocket);
}
- (void)didReceiveMessage:(NSString *)message fromAddress:(NSString *)address
{
}
@furueili
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hi changxi wu,

I see ur udp post on the github -> https://gist.github.com/chancyWu/8349411
and I use ur function for test is worked,
but I found issue the udp server send echo message back to client ,
client's recvfrom function response is -1 ,

could u please give me some hint ?

PS. the udp server in my mac is CocoaAsyncSocket UdpEchoServer Sample
https://github.com/robbiehanson/CocoaAsyncSocket

@luisAzcuaga
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luisAzcuaga commented Dec 7, 2018

Did you manage to make it work? Anywhere to find your code?

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