From fd0851c374ab15074be313af958d55708fcb7c63 Mon Sep 17 00:00:00 2001 From: Samuel Jero Date: Sat, 10 Nov 2012 16:57:55 -0500 Subject: [PATCH] Use a DCCP socket to reserve a source port, determine correct source address, and reply to listening sockets. --- dccpping.c | 340 +++++++++++++++++------------------------------------ 1 file changed, 108 insertions(+), 232 deletions(-) diff --git a/dccpping.c b/dccpping.c index 064c079..1eddf8c 100644 --- a/dccpping.c +++ b/dccpping.c @@ -27,6 +27,7 @@ Date: 11/2012 #include #include #include +#include #include #include #include @@ -45,7 +46,6 @@ Date: 11/2012 /*Use the DCCP source port to multiplex DCCP Ping streams by PID*/ -#define SRC_PORT_AS_PID_MULTIPLEX 1 #define DCCP_SERVICE_CODE 0x50455246 #define DEFAULT_PORT 33434 @@ -127,6 +127,7 @@ struct params{ int ip_type; /*IPv4 or IPv6*/ ipaddr_ptr_t dest_addr; /*Destination Address*/ ipaddr_ptr_t src_addr; /*Source Address*/ + int dccp_socket; /*DCCP Socket used to grab src addr/port*/ }; @@ -143,8 +144,6 @@ void handleICMP4packet(int rcv_socket); void handleICMP6packet(int rcv_socket); void buildRequestPacket(unsigned char* buffer, int *len, int seq); void updateRequestPacket(unsigned char* buffer, int *len, int seq); -void sendClose(int seq, u_int16_t ack_h, u_int32_t ack_l, int socket); -void sendReset(int seq, u_int16_t ack_h, u_int32_t ack_l, int socket); int logPacket(int req_seq, int packet_seq); int logResponse(ipaddr_ptr_t *src, int seq, int type); void clearQueue(); @@ -178,6 +177,7 @@ int main(int argc, char *argv[]) parms.ip_type=AF_UNSPEC; parms.dest_addr.gen=NULL; parms.src_addr.gen=NULL; + parms.dccp_socket=-1; sanitize_environment(); @@ -237,13 +237,6 @@ int main(int argc, char *argv[]) } dst=argv[0]; -#if SRC_PORT_AS_PID_MULTIPLEX - /*Encode PID in source port*/ - parms.src_port=(getpid()+1024)%65535; -#else - parms.src_port=parms.dest_port; -#endif - getAddresses(src, dst); if(parms.src_addr.gen==NULL || parms.dest_addr.gen==NULL){ dbgprintf(0,"Error: Can't determine source or destination address\n"); @@ -255,6 +248,7 @@ int main(int argc, char *argv[]) free(parms.src_addr.gen); free(parms.dest_addr.gen); + close(parms.dccp_socket); clearQueue(); return 0; } @@ -263,9 +257,13 @@ void getAddresses(char *src, char* dst){ struct addrinfo hint; struct addrinfo *dtmp, *stmp; struct ifaddrs *temp, *cur; - struct sockaddr_in6* iv6; + struct sockaddr_in6* iv61; + struct sockaddr_in6* iv62; + struct sockaddr_in* iv41; + struct sockaddr_in* iv42; int addrlen; int err; + char pbuf[1000]; /*Lookup destination Address*/ memset(&hint,0,sizeof(struct addrinfo)); @@ -294,6 +292,8 @@ void getAddresses(char *src, char* dst){ /*Get a meaningful source address*/ if(src!=NULL){ /*Use Commandline arg*/ + + /*Convert arg to address*/ if((err=getaddrinfo(src,NULL,&hint,&stmp))!=0){ dbgprintf(0,"Error: Source Address %s is invalid (%s)\n", src, gai_strerror(err)); exit(1); @@ -301,50 +301,113 @@ void getAddresses(char *src, char* dst){ if(stmp==NULL){ dbgprintf(0,"Error: Unknown Host %s\n", dst); exit(1); - }else{ - addrlen=stmp->ai_addrlen; - parms.src_addr.gen=malloc(stmp->ai_addrlen); - if(parms.src_addr.gen==NULL){ - dbgprintf(0,"Error: Can't allocate Memory\n"); - exit(1); - } - memcpy(parms.src_addr.gen,stmp->ai_addr,stmp->ai_addrlen); } - freeaddrinfo(stmp); - }else{ - /*Guess a good source address*/ + + /*Compare to interface addresses*/ getifaddrs(&temp); cur=temp; while(cur!=NULL){ - if(cur->ifa_addr==NULL || cur->ifa_addr->sa_family!=parms.ip_type){ + if(cur->ifa_addr==NULL || cur->ifa_addr->sa_family!=stmp->ai_family){ /*Not matching ipv4/ipv6 of dest*/ cur=cur->ifa_next; continue; } - if(cur->ifa_flags & IFF_LOOPBACK){ /*Don't use loopback addresses*/ - cur=cur->ifa_next; - continue; - } - if(cur->ifa_addr!=NULL && cur->ifa_addr->sa_family==AF_INET6){ - iv6=(struct sockaddr_in6*)cur->ifa_addr; - - if(iv6->sin6_scope_id!=0){ /*Not globally valid address, if ipv6*/ - cur=cur->ifa_next; - continue; + if(stmp->ai_family==AF_INET){ + iv41=(struct sockaddr_in*)stmp->ai_addr; + iv42=(struct sockaddr_in*)cur->ifa_addr; + if(memcmp(&iv41->sin_addr,&iv42->sin_addr, sizeof(iv41->sin_addr))==0){ + parms.src_addr.gen=malloc(sizeof(struct sockaddr_storage)); + if(parms.src_addr.gen==NULL){ + dbgprintf(0,"Error: Can't allocate Memory\n"); + exit(1); + } + parms.src_addr.gen->sa_family=parms.ip_type; + memcpy(parms.src_addr.gen,cur->ifa_addr,addrlen); + break; + } + }else{ + iv61=(struct sockaddr_in6*)stmp->ai_addr; + iv62=(struct sockaddr_in6*)cur->ifa_addr; + if(memcmp(&iv61->sin6_addr,&iv62->sin6_addr, sizeof(iv61->sin6_addr))==0){ + parms.src_addr.gen=malloc(sizeof(struct sockaddr_storage)); + if(parms.src_addr.gen==NULL){ + dbgprintf(0,"Error: Can't allocate Memory\n"); + exit(1); + } + parms.src_addr.gen->sa_family=parms.ip_type; + memcpy(parms.src_addr.gen,cur->ifa_addr,addrlen); + break; } } - - parms.src_addr.gen=malloc(sizeof(struct sockaddr_storage)); - if(parms.src_addr.gen==NULL){ - dbgprintf(0,"Error: Can't allocate Memory\n"); - exit(1); - } - parms.src_addr.gen->sa_family=parms.ip_type; - memcpy(parms.src_addr.gen,cur->ifa_addr,addrlen); - //break; cur=cur->ifa_next; } + if(parms.src_addr.gen==NULL){ + if(parms.ip_type==AF_INET){ + iv41=(struct sockaddr_in*)stmp->ai_addr; + dbgprintf(0,"Error: Source Address %s does not belong to any interface!\n", + inet_ntop(parms.ip_type, (void*)&iv41->sin_addr, pbuf, 1000)); + }else{ + iv61=(struct sockaddr_in6*)stmp->ai_addr; + dbgprintf(0,"Error: Source Address %s does not belong to any interface!\n", + inet_ntop(parms.ip_type, (void*)&iv61->sin6_addr, pbuf, 1000)); + } + exit(1); + } freeifaddrs(temp); + freeaddrinfo(stmp); + } + + /*Create socket to auto respond for open connections and reserve a source port*/ + parms.dccp_socket=socket(parms.ip_type,SOCK_DCCP, IPPROTO_DCCP); + if(parms.dccp_socket<0){ + dbgprintf(0, "Error: Failed opening DCCP Socket (%s)\n",strerror(errno)); + exit(1); + } + fcntl(parms.dccp_socket, F_SETFL, O_NONBLOCK); + + + if(parms.src_addr.gen==NULL){ + /*Auto-detect source address*/ + parms.src_addr.gen=malloc(sizeof(struct sockaddr_storage)); + if(parms.src_addr.gen==NULL){ + dbgprintf(0,"Error: Can't allocate Memory\n"); + exit(1); + } + memset(parms.src_addr.gen,0,sizeof(struct sockaddr_storage)); + parms.src_addr.gen->sa_family=parms.ip_type; + }else{ + /*Bind to the given source address*/ + if(bind(parms.dccp_socket,parms.src_addr.gen,sizeof(struct sockaddr_storage))<0){ + dbgprintf(0, "Error: Failed bind() on DCCP socket (%s)\n",strerror(errno)); + exit(1); + } + } + + /*Connect socket to get source address/port*/ + if(parms.ip_type==AF_INET){ + parms.dest_addr.ipv4->sin_port=htons(parms.dest_port); + }else{ + parms.dest_addr.ipv6->sin6_port=htons(parms.dest_port); + } + if(connect(parms.dccp_socket,parms.dest_addr.gen,sizeof(struct sockaddr_storage))<0){ + if(errno!=EINPROGRESS){ + dbgprintf(0, "Error: Failed connect() on DCCP socket (%s)\n",strerror(errno)); + exit(1); + } + } + + /*Get source address and port number!*/ + addrlen=sizeof(struct sockaddr_storage); + if(getsockname(parms.dccp_socket,parms.src_addr.gen,(socklen_t*)&addrlen)<0){ + dbgprintf(0, "Error: Failed getsockname() on DCCP socket (%s)\n",strerror(errno)); + exit(1); + } + if(parms.ip_type==AF_INET){ + parms.src_port=ntohs(parms.src_addr.ipv4->sin_port); + parms.dest_addr.ipv4->sin_port=0; + }else{ + parms.src_port=ntohs(parms.src_addr.ipv6->sin6_port); + parms.dest_addr.ipv6->sin6_port=0; } return; } @@ -410,7 +473,7 @@ void doping(){ /*Send Ping*/ if(sendto(rs, &sbuffer, slen, MSG_DONTWAIT,(struct sockaddr*)parms.dest_addr.gen,addrlen)<0){ if(errno!=EINTR){ - dbgprintf(0,"Error: sendto failed\n"); + dbgprintf(0,"Error: sendto() failed (%s)\n",strerror(errno)); } } if(parms.count==0){done=1; break;} @@ -485,7 +548,6 @@ void handleDCCPpacket(int rcv_socket, int send_socket){ socklen_t rcv_addr_len; struct dccp_hdr *dhdr; struct dccp_hdr_reset *dhdr_re; - struct dccp_hdr_ext *dhdre; struct dccp_hdr_response *dhdr_rp; struct dccp_hdr_ack_bits *dhdr_sync; unsigned char* ptr; @@ -585,13 +647,10 @@ void handleDCCPpacket(int rcv_socket, int send_socket){ } /*Log*/ - dhdre=(struct dccp_hdr_ext*)(ptr+sizeof(struct dccp_hdr)); dhdr_rp=(struct dccp_hdr_response*)(ptr+sizeof(struct dccp_hdr)+sizeof(struct dccp_hdr_ext)); logResponse(&rcv_addr,ntohl(dhdr_rp->dccph_resp_ack.dccph_ack_nr_low),RESPONSE); - /*Send Close*/ - sendClose(ntohl(dhdr_rp->dccph_resp_ack.dccph_ack_nr_low), - dhdr->dccph_seq, dhdre->dccph_seq_low,send_socket); + /*DCCP socket opened in getAddresses() will send Reset*/ } if(dhdr->dccph_type==DCCP_PKT_SYNC || dhdr->dccph_type==DCCP_PKT_SYNCACK){ if(rlen < (ptr-rbuffer)+sizeof(struct dccp_hdr)+sizeof(struct dccp_hdr_ext)+sizeof(struct dccp_hdr_ack_bits)){ @@ -600,13 +659,10 @@ void handleDCCPpacket(int rcv_socket, int send_socket){ } /*Log*/ - dhdre=(struct dccp_hdr_ext*)(ptr+sizeof(struct dccp_hdr)); dhdr_sync=(struct dccp_hdr_ack_bits*)(ptr+sizeof(struct dccp_hdr)+sizeof(struct dccp_hdr_ext)); logResponse(&rcv_addr,ntohl(dhdr_sync->dccph_ack_nr_low),SYNC); - /*Send Reset*/ - sendReset(ntohl(dhdr_sync->dccph_ack_nr_low), - dhdr->dccph_seq, dhdre->dccph_seq_low,send_socket); + /*DCCP socket opened in getAddresses() will send Reset*/ } free(rcv_addr.gen); @@ -935,186 +991,6 @@ void updateRequestPacket(unsigned char* buffer, int *len, int seq){ return; } -void sendClose(int seq, u_int16_t ack_h, u_int32_t ack_l, int socket){ - unsigned char buffer[1500]; - struct dccp_hdr *dhdr; - struct dccp_hdr_ext *dhdre; - struct dccp_hdr_ack_bits *dhd_ack; - struct iphdr* ip4hdr; - struct ip6_hdr* ip6hdr; - int len; - int addrlen; - - int ip_hdr_len; - int dccp_hdr_len=sizeof(struct dccp_hdr)+sizeof(struct dccp_hdr_ext)+sizeof(struct dccp_hdr_ack_bits); - - memset(buffer, 0, 1500); - - /*IP header*/ - ip4hdr=NULL; - if(parms.ip_type==AF_INET){ - ip_hdr_len=sizeof(struct iphdr); - ip4hdr=(struct iphdr*)buffer; - ip4hdr->check=htons(0); - memcpy(&ip4hdr->daddr, &parms.dest_addr.ipv4->sin_addr, sizeof(parms.dest_addr.ipv4->sin_addr)); - ip4hdr->frag_off=htons(0); - ip4hdr->id=htons(1);//first - ip4hdr->ihl=5; - ip4hdr->protocol=IPPROTO_DCCP; - memcpy(&ip4hdr->saddr, &parms.src_addr.ipv4->sin_addr, sizeof(parms.src_addr.ipv4->sin_addr)); - ip4hdr->tos=0; - ip4hdr->tot_len=htons(ip_hdr_len+dccp_hdr_len); - ip4hdr->ttl=parms.ttl; - ip4hdr->version=4; - }else{ - ip_hdr_len=sizeof(struct ip6_hdr); - ip6hdr=(struct ip6_hdr*)buffer; - memcpy(&ip6hdr->ip6_dst, &parms.dest_addr.ipv6->sin6_addr, sizeof(parms.dest_addr.ipv6->sin6_addr)); - memcpy(&ip6hdr->ip6_src, &parms.src_addr.ipv6->sin6_addr, sizeof(parms.src_addr.ipv6->sin6_addr)); - ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_flow=htonl(6<<28); //version, traffic class, flow label - ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_hlim=parms.ttl; - ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_nxt=IPPROTO_DCCP; - ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_plen=htons(dccp_hdr_len); - } - - /*DCCP header*/ - dhdr=(struct dccp_hdr*)(buffer+ip_hdr_len); - dhdre=(struct dccp_hdr_ext*)(buffer+ip_hdr_len+sizeof(struct dccp_hdr)); - dhd_ack=(struct dccp_hdr_ack_bits*)(buffer+ip_hdr_len+sizeof(struct dccp_hdr)+sizeof(struct dccp_hdr_ext)); - dhdr->dccph_ccval=0; - dhdr->dccph_checksum=0; - dhdr->dccph_cscov=0; - dhdr->dccph_doff=dccp_hdr_len/4; - dhdr->dccph_dport=htons(parms.dest_port); - dhdr->dccph_reserved=0; - dhdr->dccph_sport=htons(parms.src_port); - dhdr->dccph_x=1; - dhdr->dccph_type=DCCP_PKT_CLOSE; - dhdr->dccph_seq2=htonl(0); //Reserved if using 48 bit sequence numbers - dhdr->dccph_seq=htonl(0); //High 16bits of sequence number. Always make 0 for simplicity. - dhdre->dccph_seq_low=htonl(seq+1); - dhd_ack->dccph_ack_nr_high=ack_h; - dhd_ack->dccph_ack_nr_low=ack_l; - - /*Checksums*/ - if(parms.ip_type==AF_INET){ - dhdr->dccph_checksum=ipv4_pseudohdr_chksum((buffer+ip_hdr_len), dccp_hdr_len, - (unsigned char*) &parms.dest_addr.ipv4->sin_addr, - (unsigned char*)&parms.src_addr.ipv4->sin_addr, IPPROTO_DCCP); - ip4hdr->check=ipv4_chksum(buffer,ip_hdr_len); - }else{ - dhdr->dccph_checksum=ipv6_pseudohdr_chksum((buffer+ip_hdr_len), dccp_hdr_len, - (unsigned char*) &parms.dest_addr.ipv6->sin6_addr, - (unsigned char*)&parms.src_addr.ipv6->sin6_addr, IPPROTO_DCCP); - } - len=ip_hdr_len+dccp_hdr_len; - - /*Send*/ - if(parms.ip_type==AF_INET){ - addrlen=sizeof(struct sockaddr_in); - }else{ - addrlen=sizeof(struct sockaddr_in6); - } - if(sendto(socket, &buffer, len, MSG_DONTWAIT,(struct sockaddr*)parms.dest_addr.gen,addrlen)<0){ - if(errno!=EINTR){ - dbgprintf(0,"Error: sendto failed\n"); - } - } - return; -} - -void sendReset(int seq, u_int16_t ack_h, u_int32_t ack_l, int socket){ - unsigned char buffer[1500]; - struct dccp_hdr *dhdr; - struct dccp_hdr_ext *dhdre; - struct dccp_hdr_reset *dh_re; - struct iphdr* ip4hdr; - struct ip6_hdr* ip6hdr; - int len; - int addrlen; - - int ip_hdr_len; - int dccp_hdr_len=sizeof(struct dccp_hdr)+sizeof(struct dccp_hdr_ext)+sizeof(struct dccp_hdr_reset); - - memset(buffer, 0, 1500); - - /*IP header*/ - ip4hdr=NULL; - if(parms.ip_type==AF_INET){ - ip_hdr_len=sizeof(struct iphdr); - ip4hdr=(struct iphdr*)buffer; - ip4hdr->check=htons(0); - memcpy(&ip4hdr->daddr, &parms.dest_addr.ipv4->sin_addr, sizeof(parms.dest_addr.ipv4->sin_addr)); - ip4hdr->frag_off=htons(0); - ip4hdr->id=htons(1);//first - ip4hdr->ihl=5; - ip4hdr->protocol=IPPROTO_DCCP; - memcpy(&ip4hdr->saddr, &parms.src_addr.ipv4->sin_addr, sizeof(parms.src_addr.ipv4->sin_addr)); - ip4hdr->tos=0; - ip4hdr->tot_len=htons(ip_hdr_len+dccp_hdr_len); - ip4hdr->ttl=parms.ttl; - ip4hdr->version=4; - }else{ - ip_hdr_len=sizeof(struct ip6_hdr); - ip6hdr=(struct ip6_hdr*)buffer; - memcpy(&ip6hdr->ip6_dst, &parms.dest_addr.ipv6->sin6_addr, sizeof(parms.dest_addr.ipv6->sin6_addr)); - memcpy(&ip6hdr->ip6_src, &parms.src_addr.ipv6->sin6_addr, sizeof(parms.src_addr.ipv6->sin6_addr)); - ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_flow=htonl(6<<28); //version, traffic class, flow label - ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_hlim=parms.ttl; - ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_nxt=IPPROTO_DCCP; - ip6hdr->ip6_ctlun.ip6_un1.ip6_un1_plen=htons(dccp_hdr_len); - } - - /*DCCP header*/ - dhdr=(struct dccp_hdr*)(buffer+ip_hdr_len); - dhdre=(struct dccp_hdr_ext*)(buffer+ip_hdr_len+sizeof(struct dccp_hdr)); - dh_re=(struct dccp_hdr_reset*)(buffer+ip_hdr_len+sizeof(struct dccp_hdr)+sizeof(struct dccp_hdr_ext)); - dhdr->dccph_ccval=0; - dhdr->dccph_checksum=0; - dhdr->dccph_cscov=0; - dhdr->dccph_doff=dccp_hdr_len/4; - dhdr->dccph_dport=htons(parms.dest_port); - dhdr->dccph_reserved=0; - dhdr->dccph_sport=htons(parms.src_port); - dhdr->dccph_x=1; - dhdr->dccph_type=DCCP_PKT_RESET; - dhdr->dccph_seq2=htonl(0); //Reserved if using 48 bit sequence numbers - dhdr->dccph_seq=htonl(0); //High 16bits of sequence number. Always make 0 for simplicity. - dhdre->dccph_seq_low=htonl(seq+1); - dh_re->dccph_reset_ack.dccph_ack_nr_high=ack_h; - dh_re->dccph_reset_ack.dccph_ack_nr_low=ack_l; - dh_re->dccph_reset_code=DCCP_RESET_CODE_CLOSED; - dh_re->dccph_reset_data[0]=0; - dh_re->dccph_reset_data[1]=0; - dh_re->dccph_reset_data[2]=0; - - /*Checksums*/ - if(parms.ip_type==AF_INET){ - dhdr->dccph_checksum=ipv4_pseudohdr_chksum((buffer+ip_hdr_len), dccp_hdr_len, - (unsigned char*) &parms.dest_addr.ipv4->sin_addr, - (unsigned char*)&parms.src_addr.ipv4->sin_addr, IPPROTO_DCCP); - ip4hdr->check=ipv4_chksum(buffer,ip_hdr_len); - }else{ - dhdr->dccph_checksum=ipv6_pseudohdr_chksum((buffer+ip_hdr_len), dccp_hdr_len, - (unsigned char*) &parms.dest_addr.ipv6->sin6_addr, - (unsigned char*)&parms.src_addr.ipv6->sin6_addr, IPPROTO_DCCP); - } - len=ip_hdr_len+dccp_hdr_len; - - /*Send*/ - if(parms.ip_type==AF_INET){ - addrlen=sizeof(struct sockaddr_in); - }else{ - addrlen=sizeof(struct sockaddr_in6); - } - if(sendto(socket, &buffer, len, MSG_DONTWAIT,(struct sockaddr*)parms.dest_addr.gen,addrlen)<0){ - if(errno!=EINTR){ - dbgprintf(0,"Error: sendto failed\n"); - } - } - return; -} - int logPacket(int req_seq, int packet_seq){ struct request *tmp; -- 2.39.2