X-Git-Url: http://dolda2000.com/gitweb/?a=blobdiff_plain;f=icmpdnd.c;h=1dfb0286b5be139234e2d7a5d4c97c4388ff6219;hb=df4e01a579663cd726eb2b3c2d5d8800cf2c3f0c;hp=0169e6daf552da7e759c03cc8c0f6d87442ecc90;hpb=fa6ac2fc3180a275d59bff8da4e4883fd40a5de7;p=icmp-dn.git

diff --git a/icmpdnd.c b/icmpdnd.c
index 0169e6d..1dfb028 100644
--- a/icmpdnd.c
+++ b/icmpdnd.c
@@ -1,6 +1,6 @@
 /*
  *  icmpdnd - ICMP Domain Name responder daemon for Linux
- *  Copyright (C) 2004 Fredrik Tolf <fredrik@dolda2000.com>
+ *  Copyright (C) 2005 Fredrik Tolf <fredrik@dolda2000.com>
  *  
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -21,7 +21,10 @@
 #include <stdio.h>
 #include <string.h>
 #include <errno.h>
+#include <syslog.h>
+#include <time.h>
 #include <sys/socket.h>
+#include <sys/poll.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <netinet/ip.h>
@@ -53,8 +56,6 @@ struct rephdr {
 #define ICMP_NAMEREQ 37
 #define ICMP_NAMEREP 38
 
-#define TTL 3600
-
 volatile int alive;
 
 size_t filldn(char *dst)
@@ -130,56 +131,151 @@ void cksum(void *hdr, size_t len)
 
 int main(int argc, char **argv)
 {
-    int ret;
-    int s, namelen, datalen;
+    int i, n, ret;
+    int c, cs, s4, s6, datalen;
+    int daemonize, ttl;
     unsigned char buf[65536];
-    struct sockaddr_in name;
+    struct sockaddr_storage name;
     struct reqhdr req;
     struct rephdr rep;
     struct iphdr iphdr;
-
-    if((s = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP)) < 0) {
-	perror("could not create raw socket");
+    struct msghdr mhdr;
+    struct iovec iov;
+    char cmsgbuf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
+    size_t hdrlen;
+    struct pollfd pfd[2];
+    time_t curtime, lasterr;
+    
+    daemonize = 1;
+    ttl = 3600;
+    while((c = getopt(argc, argv, "nht:")) != -1) {
+	switch(c) {
+	case 't':
+	    ttl = atoi(optarg);
+	    break;
+	case 'n':
+	    daemonize = 0;
+	    break;
+	case 'h':
+	case '?':
+	case ':':
+	default:
+	    fprintf(stderr, "usage: icmpdnd [-n]");
+	    exit((c == 'h')?0:1);
+	}
+    }
+    
+    s4 = socket(PF_INET, SOCK_RAW, IPPROTO_ICMP);
+    s6 = socket(PF_INET6, SOCK_RAW, IPPROTO_ICMP);
+    if((s4 < 0) && (s6 < 0)) {
+	perror("could not open raw socket");
 	exit(1);
     }
+    if(s6 >= 0) {
+	i = 1;
+	if(setsockopt(s6, IPPROTO_IPV6, IPV6_PKTINFO, &i, sizeof(i))) {
+	    perror("could not set IPV6_PKTINFO sockopt");
+	    exit(1);
+	}
+    }
+    
+    if(daemonize)
+	daemon(0, 0);
+    
+    openlog("icmpdnd", LOG_PID | LOG_NDELAY, LOG_DAEMON);
     
     alive = 1;
+    lasterr = 0;
     while(alive) {
-	namelen = sizeof(name);
-	ret = recvfrom(s, buf, sizeof(buf), 0, (struct sockaddr *)&name, &namelen);
+	n = 0;
+	if(s4 >= 0) {
+	    pfd[n].fd = s4;
+	    pfd[n].events = POLLIN;
+	    n++;
+	}
+	if(s6 >= 0) {
+	    pfd[n].fd = s6;
+	    pfd[n].events = POLLIN;
+	    n++;
+	}
+	ret = poll(pfd, n, -1);
+
+	curtime = time(NULL);
 	if(ret < 0) {
 	    if(errno == EINTR)
 		continue;
-	    perror("recvfrom");
-	    exit(1);
+	    syslog(LOG_ERR, "error while polling sockets: %m");
+	    if(lasterr == curtime) {
+		syslog(LOG_CRIT, "exiting due to repeated errors");
+		exit(1);
+	    }
+	    lasterr = curtime;
 	}
-	if(ret < sizeof(iphdr))
-	    continue;
-	memcpy(&iphdr, buf, sizeof(iphdr));
-	if(iphdr.protocol != IPPROTO_ICMP)
-	    continue;
-	if(ret < sizeof(iphdr) + sizeof(req))
-	    continue;
-	memcpy(&req, buf + sizeof(iphdr), sizeof(req));
-	if(req.type != ICMP_NAMEREQ)
-	    continue;
-	rep.type = ICMP_NAMEREP;
-	rep.code = 0;
-	rep.id = req.id;
-	rep.seq = req.seq;
-	rep.ttl = htonl(TTL);
-	memcpy(buf, &rep, sizeof(rep));
-	datalen = filldn(buf + sizeof(rep));
-
-	cksum(buf, datalen + sizeof(rep));
-
-	ret = sendto(s, buf, datalen + sizeof(rep), 0, (struct sockaddr *)&name, namelen);
-	if(ret < 0) {
-	    perror("sendto");
-	    exit(1);
+	
+	for(i = 0; i < n; i++) {
+	    if((pfd[i].revents & POLLIN) == 0)
+		continue;
+	    cs = pfd[i].fd;
+	    memset(&name, 0, sizeof(name));
+	    
+	    iov.iov_len = sizeof(buf);
+	    iov.iov_base = buf;
+	    mhdr.msg_name = &name;
+	    mhdr.msg_namelen = sizeof(name);
+	    mhdr.msg_iov = &iov;
+	    mhdr.msg_iovlen = 1;
+	    mhdr.msg_control = cmsgbuf;
+	    mhdr.msg_controllen = sizeof(cmsgbuf);
+	    
+	    ret = recvmsg(cs, &mhdr, 0);
+	    if(ret < 0) {
+		syslog(LOG_WARNING, "error while receiving datagram: %m");
+		continue;
+	    }
+	    
+	    if(cs == s4) {
+		if(ret < sizeof(iphdr) + sizeof(req))
+		    continue;
+		hdrlen = sizeof(iphdr);
+		memcpy(&iphdr, buf, sizeof(iphdr));
+		if(iphdr.protocol != IPPROTO_ICMP)
+		    continue;
+		mhdr.msg_control = NULL;
+		mhdr.msg_controllen = 0;
+	    } else if(cs == s6) {
+		if(ret < sizeof(req))
+		    continue;
+		((struct sockaddr_in6 *)&name)->sin6_port = 0;
+		hdrlen = 0;
+		/* Just keep mhdr.msg_control. */
+	    } else {
+		syslog(LOG_CRIT, "strangeness!");
+		abort();
+	    }
+	    memcpy(&req, buf + hdrlen, sizeof(req));
+	    if(req.type != ICMP_NAMEREQ)
+		continue;
+	    rep.type = ICMP_NAMEREP;
+	    rep.code = 0;
+	    rep.id = req.id;
+	    rep.seq = req.seq;
+	    rep.ttl = htonl(ttl);
+	    memcpy(buf, &rep, sizeof(rep));
+	    datalen = filldn(buf + sizeof(rep));
+	
+	    cksum(buf, datalen + sizeof(rep));
+	    
+	    iov.iov_len = sizeof(rep) + datalen;
+	    iov.iov_base = buf;
+	    mhdr.msg_iov = &iov;
+	    mhdr.msg_iovlen = 1;
+	    ret = sendmsg(cs, &mhdr, 0);
+	    if(ret < 0)
+		syslog(LOG_WARNING, "error in sending reply: %m");
 	}
     }
     
-    close(s);
+    close(s4);
+    close(s6);
     return(0);
 }