Ticket #21225: patch-dnsspoof.c.diff

dnsspoof.c

@@ -38 +38 @@
 
 pcap_t          *pcap_pd = NULL;
 int              pcap_off = -1;
-int              lnet_sock = -1;
+libnet_t        *l;
 u_long           lnet_ip = -1;
 
 static void
@@ -90 +90 @@
 dns_init(char *dev, char *filename)
 {
         FILE *f;
-        struct libnet_link_int *llif;
+        libnet_t *l;
+        char libnet_ebuf[LIBNET_ERRBUF_SIZE];
         struct dnsent *de;
         char *ip, *name, buf[1024];
 
-        if ((llif = libnet_open_link_interface(dev, buf)) == NULL)
-                errx(1, "%s", buf);
+        if ((l = libnet_init(LIBNET_LINK, dev, libnet_ebuf)) == NULL)
+                errx(1, "%s", libnet_ebuf);
         
-        if ((lnet_ip = libnet_get_ipaddr(llif, dev, buf)) == -1)
-                errx(1, "%s", buf);
+        if ((lnet_ip = libnet_get_ipaddr4(l)) == -1)
+                errx(1, "%s", libnet_geterror(l));
 
-        lnet_ip = htonl(lnet_ip);
-        
-        libnet_close_link_interface(llif);
+        libnet_destroy(l);
 
         SLIST_INIT(&dns_entries);
         
@@ -180 +179 @@
 static void
 dns_spoof(u_char *u, const struct pcap_pkthdr *pkthdr, const u_char *pkt)
 {
-        struct libnet_ip_hdr *ip;
+        struct libnet_ipv4_hdr *ip;
         struct libnet_udp_hdr *udp;
         HEADER *dns;
         char name[MAXHOSTNAMELEN];
@@ -189 +188 @@
         in_addr_t dst;
         u_short type, class;
 
-        ip = (struct libnet_ip_hdr *)(pkt + pcap_off);
+        ip = (struct libnet_ipv4_hdr *)(pkt + pcap_off);
         udp = (struct libnet_udp_hdr *)(pkt + pcap_off + (ip->ip_hl * 4));
         dns = (HEADER *)(udp + 1);
         p = (u_char *)(dns + 1);
@@ -212 +211 @@
         if (class != C_IN)
                 return;
 
-        p = buf + IP_H + UDP_H + dnslen;
+        p = buf + dnslen;
         
         if (type == T_A) {
                 if ((dst = dns_lookup_a(name)) == -1)
@@ -234 +233 @@
                 anslen += 12;
         }
         else return;
-        
-        libnet_build_ip(UDP_H + dnslen + anslen, 0, libnet_get_prand(PRu16),
-                        0, 64, IPPROTO_UDP, ip->ip_dst.s_addr,
-                        ip->ip_src.s_addr, NULL, 0, buf);
-        
-        libnet_build_udp(ntohs(udp->uh_dport), ntohs(udp->uh_sport),
-                         NULL, dnslen + anslen, buf + IP_H);
 
-        memcpy(buf + IP_H + UDP_H, (u_char *)dns, dnslen);
+        memcpy(buf, (u_char *)dns, dnslen);
 
-        dns = (HEADER *)(buf + IP_H + UDP_H);
+        dns = (HEADER *)buf;
         dns->qr = dns->ra = 1;
         if (type == T_PTR) dns->aa = 1;
         dns->ancount = htons(1);
 
         dnslen += anslen;
+
+        libnet_clear_packet(l);
+        libnet_build_udp(ntohs(udp->uh_dport), ntohs(udp->uh_sport),
+                         LIBNET_UDP_H + dnslen, 0,
+                         (u_int8_t *)buf, dnslen, l, 0);
+
+        libnet_build_ipv4(LIBNET_IPV4_H + LIBNET_UDP_H + dnslen, 0,
+                          libnet_get_prand(LIBNET_PRu16), 0, 64, IPPROTO_UDP, 0,
+                          ip->ip_dst.s_addr, ip->ip_src.s_addr, NULL, 0, l, 0);
         
-        libnet_do_checksum(buf, IPPROTO_UDP, UDP_H + dnslen);
-        
-        if (libnet_write_ip(lnet_sock, buf, IP_H + UDP_H + dnslen) < 0)
+        if (libnet_write(l) < 0)
                 warn("write");
 
         fprintf(stderr, "%s.%d > %s.%d:  %d+ %s? %s\n",
-              libnet_host_lookup(ip->ip_src.s_addr, 0), ntohs(udp->uh_sport),
-              libnet_host_lookup(ip->ip_dst.s_addr, 0), ntohs(udp->uh_dport),
+              libnet_addr2name4(ip->ip_src.s_addr, 0), ntohs(udp->uh_sport),
+              libnet_addr2name4(ip->ip_dst.s_addr, 0), ntohs(udp->uh_dport),
               ntohs(dns->id), type == T_A ? "A" : "PTR", name);
 }
 
 static void
 cleanup(int sig)
 {
-        libnet_close_raw_sock(lnet_sock);
+        libnet_destroy(l);
         pcap_close(pcap_pd);
         exit(0);
 }
@@ -276 +275 @@
         extern char *optarg;
         extern int optind;
         char *p, *dev, *hosts, buf[1024];
+        char ebuf[LIBNET_ERRBUF_SIZE];
         int i;
 
         dev = hosts = NULL;
@@ -306 +306 @@
                 strlcpy(buf, p, sizeof(buf));
         }
         else snprintf(buf, sizeof(buf), "udp dst port 53 and not src %s",
-                      libnet_host_lookup(lnet_ip, 0));
+                      libnet_addr2name4(lnet_ip, LIBNET_DONT_RESOLVE));
         
         if ((pcap_pd = pcap_init(dev, buf, 128)) == NULL)
                 errx(1, "couldn't initialize sniffing");
@@ -314 +314 @@
         if ((pcap_off = pcap_dloff(pcap_pd)) < 0)
                 errx(1, "couldn't determine link layer offset");
         
-        if ((lnet_sock = libnet_open_raw_sock(IPPROTO_RAW)) == -1)
+        if ((l = libnet_init(LIBNET_RAW4, dev, ebuf)) == NULL)
                 errx(1, "couldn't initialize sending");
         
-        libnet_seed_prand();
+        libnet_seed_prand(l);
         
         signal(SIGHUP, cleanup);
         signal(SIGINT, cleanup);