mhttp.c

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <malloc.h>
#include <stdio.h>
#include <stdlib.h>

#include "mdnsd.h"
#include "sdtxt.h"

// conflict!
void con(char *name, int type, void *arg)
{
    printf("conflicting name detected %s for type %d\n",name,type);
    exit(1);
}

// quit
int _shutdown = 0;
mdnsd _d;
int _zzz[2];
void done(int sig)
{
    _shutdown = 1;
    mdnsd_shutdown(_d);
    write(_zzz[1]," ",1);
}

// create multicast 224.0.0.251:5353 socket
int msock()
{
    int s, flag = 1, ittl = 255;
    struct sockaddr_in in;
    struct ip_mreq mc;
    char ttl = 255;

    bzero(&in, sizeof(in));
    in.sin_family = AF_INET;
    in.sin_port = htons(5353);
    in.sin_addr.s_addr = 0;

    if((s = socket(AF_INET,SOCK_DGRAM,0)) < 0) return 0;
#ifdef SO_REUSEPORT
    setsockopt(s, SOL_SOCKET, SO_REUSEPORT, (char*)&flag, sizeof(flag));
#endif
    setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char*)&flag, sizeof(flag));
    if(bind(s,(struct sockaddr*)&in,sizeof(in))) { close(s); return 0; }

    mc.imr_multiaddr.s_addr = inet_addr("224.0.0.251");
    mc.imr_interface.s_addr = htonl(INADDR_ANY);
    setsockopt(s, IPPROTO_IP, IP_ADD_MEMBERSHIP, &mc, sizeof(mc)); 
    setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl));
    setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, &ittl, sizeof(ittl));

    flag =  fcntl(s, F_GETFL, 0);
    flag |= O_NONBLOCK;
    fcntl(s, F_SETFL, flag);

    return s;
}

int main(int argc, char *argv[])
{
    mdnsd d;
    mdnsdr r;
    struct message m;
    struct in_addr ip;
    unsigned short int port;
    struct timeval *tv;
    int bsize, ssize = sizeof(struct sockaddr_in);
    unsigned char buf[MAX_PACKET_LEN];
    struct sockaddr_in from, to;
    fd_set fds;
    int s;
    unsigned char *packet, hlocal[256], nlocal[256];
    int len = 0;
    xht h;

    if(argc < 4) { printf("usage: mhttp 'unique name' 12.34.56.78 80 '/optionalpath'\n"); return; }

    ip.s_addr = inet_addr(argv[2]);
    port = atoi(argv[3]);
    printf("Announcing .local site named '%s' to %s:%d and extra path '%s'\n",argv[1],inet_ntoa(ip),port,argv[4]);

    signal(SIGINT,done);
    signal(SIGHUP,done);
    signal(SIGQUIT,done);
    signal(SIGTERM,done);
    pipe(_zzz);
    _d = d = mdnsd_new(QCLASS_IN,1000);
    if((s = msock()) == 0) { printf("can't create socket: %s\n",strerror(errno)); return 1; }

    sprintf(hlocal,"%s._http._tcp.local.",argv[1]);
    sprintf(nlocal,"http-%s.local.",argv[1]);
    r = mdnsd_shared(d,"_http._tcp.local.",QTYPE_PTR,120);
    mdnsd_set_host(d,r,hlocal);
    r = mdnsd_unique(d,hlocal,QTYPE_SRV,600,con,0);
    mdnsd_set_srv(d,r,0,0,port,nlocal);
    r = mdnsd_unique(d,nlocal,QTYPE_A,600,con,0);
    mdnsd_set_raw(d,r,(unsigned char *)&ip,4);
    r = mdnsd_unique(d,hlocal,QTYPE_TXT,600,con,0);
    h = xht_new(11);
    if(argc == 5 && argv[4] && strlen(argv[4]) > 0) xht_set(h,"path",argv[4]);
    packet = sd2txt(h, &len);
    xht_free(h);
    mdnsd_set_raw(d,r,packet,len);
    free(packet);

    while(1)
    {
        tv = mdnsd_sleep(d);
        FD_ZERO(&fds);
        FD_SET(_zzz[0],&fds);
        FD_SET(s,&fds);
        select(s+1,&fds,0,0,tv);

        // only used when we wake-up from a signal, shutting down
        if(FD_ISSET(_zzz[0],&fds)) read(_zzz[0],buf,MAX_PACKET_LEN);

        if(FD_ISSET(s,&fds))
        {
            while((bsize = recvfrom(s,buf,MAX_PACKET_LEN,0,(struct sockaddr*)&from,&ssize)) > 0)
            {
                bzero(&m,sizeof(struct message));
                message_parse(&m,buf);
                mdnsd_in(d,&m,(unsigned long int)from.sin_addr.s_addr,from.sin_port);
            }
            if(bsize < 0 && errno != EAGAIN) { printf("can't read from socket %d: %s\n",errno,strerror(errno)); return 1; }
        }
        while(mdnsd_out(d,&m,(long unsigned int*)&ip.s_addr,&port))
        {
            bzero(&to, sizeof(to));
            to.sin_family = AF_INET;
            to.sin_port = port;
            to.sin_addr.s_addr = ip.s_addr;
            if(sendto(s,message_packet(&m),message_packet_len(&m),0,(struct sockaddr *)&to,sizeof(struct sockaddr_in)) != message_packet_len(&m))  { printf("can't write to socket: %s\n",strerror(errno)); return 1; }
        }
        if(_shutdown) break;
    }

    mdnsd_shutdown(d);
    mdnsd_free(d);
    return 0;
}