get_routing_table.c0000644000000000000000000001061310310273723014654 0ustar rootroot00000000000000// author : Asanga Udugama (adu@comnets.uni-bremen.de) // date : 2005-09-10 // compile & link : gcc -o get_routing_table get_routing_table.c #include #include #include #include // buffer to hold the RTNETLINK request struct { struct nlmsghdr nl; struct rtmsg rt; char buf[8192]; } req; // variables used for // socket communications int fd; struct sockaddr_nl la; struct sockaddr_nl pa; struct msghdr msg; struct iovec iov; int rtn; // buffer to hold the RTNETLINK reply(ies) char buf[8192]; // RTNETLINK message pointers & lengths // used when processing messages struct nlmsghdr *nlp; int nll; struct rtmsg *rtp; int rtl; struct rtattr *rtap; void send_request() { // create the remote address // to communicate bzero(&pa, sizeof(pa)); pa.nl_family = AF_NETLINK; // initialize & create the struct msghdr supplied // to the sendmsg() function bzero(&msg, sizeof(msg)); msg.msg_name = (void *) &pa; msg.msg_namelen = sizeof(pa); // place the pointer & size of the RTNETLINK // message in the struct msghdr iov.iov_base = (void *) &req.nl; iov.iov_len = req.nl.nlmsg_len; msg.msg_iov = &iov; msg.msg_iovlen = 1; // send the RTNETLINK message to kernel rtn = sendmsg(fd, &msg, 0); } void recv_reply() { char *p; // initialize the socket read buffer bzero(buf, sizeof(buf)); p = buf; nll = 0; // read from the socket until the NLMSG_DONE is // returned in the type of the RTNETLINK message // or if it was a monitoring socket while(1) { rtn = recv(fd, p, sizeof(buf) - nll, 0); nlp = (struct nlmsghdr *) p; if(nlp->nlmsg_type == NLMSG_DONE) break; // increment the buffer pointer to place // next message p += rtn; // increment the total size by the size of // the last received message nll += rtn; if((la.nl_groups & RTMGRP_IPV4_ROUTE) == RTMGRP_IPV4_ROUTE) break; } } void form_request() { // initialize the request buffer bzero(&req, sizeof(req)); // set the NETLINK header req.nl.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg)); req.nl.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP; req.nl.nlmsg_type = RTM_GETROUTE; // set the routing message header req.rt.rtm_family = AF_INET; req.rt.rtm_table = RT_TABLE_MAIN; } void read_reply() { // string to hold content of the route // table (i.e. one entry) char dsts[24], gws[24], ifs[16], ms[24]; // outer loop: loops thru all the NETLINK // headers that also include the route entry // header nlp = (struct nlmsghdr *) buf; for(;NLMSG_OK(nlp, nll);nlp=NLMSG_NEXT(nlp, nll)) { // get route entry header rtp = (struct rtmsg *) NLMSG_DATA(nlp); // we are only concerned about the // main route table if(rtp->rtm_table != RT_TABLE_MAIN) continue; // init all the strings bzero(dsts, sizeof(dsts)); bzero(gws, sizeof(gws)); bzero(ifs, sizeof(ifs)); bzero(ms, sizeof(ms)); // inner loop: loop thru all the attributes of // one route entry rtap = (struct rtattr *) RTM_RTA(rtp); rtl = RTM_PAYLOAD(nlp); for(;RTA_OK(rtap, rtl);rtap=RTA_NEXT(rtap,rtl)) { switch(rtap->rta_type) { // destination IPv4 address case RTA_DST: inet_ntop(AF_INET, RTA_DATA(rtap), dsts, 24); break; // next hop IPv4 address case RTA_GATEWAY: inet_ntop(AF_INET, RTA_DATA(rtap), gws, 24); break; // unique ID associated with the network // interface case RTA_OIF: sprintf(ifs, "%d", *((int *) RTA_DATA(rtap))); default: break; } } sprintf(ms, "%d", rtp->rtm_dst_len); printf("dst %s/%s gw %s if %s\n", dsts, ms, gws, ifs); } } int main(int argc, char *argv[]) { // open socket fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); // setup local address & bind using // this address bzero(&la, sizeof(la)); la.nl_family = AF_NETLINK; la.nl_pid = getpid(); bind(fd, (struct sockaddr*) &la, sizeof(la)); // sub functions to create RTNETLINK message, // send over socket, reveive reply & process // message form_request(); send_request(); recv_reply(); read_reply(); // close socket close(fd); } set_routing_table.c0000644000000000000000000000606610310273531014674 0ustar rootroot00000000000000// author : Asanga Udugama (adu@comnets.uni-bremen.de) // date : 2005-09-10 // compile & link : gcc -o set_routing_table set_routing_table.c #include #include #include #include // buffer to hold the RTNETLINK request struct { struct nlmsghdr nl; struct rtmsg rt; char buf[8192]; } req; // variables used for // socket communications int fd; struct sockaddr_nl la; struct sockaddr_nl pa; struct msghdr msg; struct iovec iov; int rtn; // buffer to hold the RTNETLINK reply(ies) char buf[8192]; // RTNETLINK message pointers & lengths // used when processing messages struct nlmsghdr *nlp; int nll; struct rtmsg *rtp; int rtl; struct rtattr *rtap; void send_request() { // create the remote address // to communicate bzero(&pa, sizeof(pa)); pa.nl_family = AF_NETLINK; // initialize & create the struct msghdr supplied // to the sendmsg() function bzero(&msg, sizeof(msg)); msg.msg_name = (void *) &pa; msg.msg_namelen = sizeof(pa); // place the pointer & size of the RTNETLINK // message in the struct msghdr iov.iov_base = (void *) &req.nl; iov.iov_len = req.nl.nlmsg_len; msg.msg_iov = &iov; msg.msg_iovlen = 1; // send the RTNETLINK message to kernel rtn = sendmsg(fd, &msg, 0); } void form_request() { // attributes of the route entry char dsts[24] = "134.102.155.14"; int ifcn = 2, pn = 32; // initalize RTNETLINK request buffer bzero(&req, sizeof(req)); // compute the initial length of the // service request rtl = sizeof(struct rtmsg); // add first attrib: // set destnation IP addr and increment the // RTNETLINK buffer size rtap = (struct rtattr *) req.buf; rtap->rta_type = RTA_DST; rtap->rta_len = sizeof(struct rtattr) + 4; inet_pton(AF_INET, dsts, ((char *)rtap) + sizeof(struct rtattr)); rtl += rtap->rta_len; // add second attrib: // set ifc index and increment the size rtap = (struct rtattr *) (((char *)rtap) + rtap->rta_len); rtap->rta_type = RTA_OIF; rtap->rta_len = sizeof(struct rtattr) + 4; memcpy(((char *)rtap) + sizeof(struct rtattr), &ifcn, 4); rtl += rtap->rta_len; // setup the NETLINK header req.nl.nlmsg_len = NLMSG_LENGTH(rtl); req.nl.nlmsg_flags = NLM_F_REQUEST | NLM_F_CREATE; req.nl.nlmsg_type = RTM_NEWROUTE; // setup the service header (struct rtmsg) req.rt.rtm_family = AF_INET; req.rt.rtm_table = RT_TABLE_MAIN; req.rt.rtm_protocol = RTPROT_STATIC; req.rt.rtm_scope = RT_SCOPE_UNIVERSE; req.rt.rtm_type = RTN_UNICAST; // set the network prefix size req.rt.rtm_dst_len = pn; } int main(int argc, char *argv[]) { // open socket fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); // setup local address & bind using // this address bzero(&la, sizeof(la)); la.nl_family = AF_NETLINK; la.nl_pid = getpid(); bind(fd, (struct sockaddr*) &la, sizeof(la)); // sub functions to create RTNETLINK message, // send over socket, reveive reply & process // message form_request(); send_request(); // close socket close(fd); } mon_routing_table.c0000644000000000000000000000674010310273765014702 0ustar rootroot00000000000000// author : Asanga Udugama (adu@comnets.uni-bremen.de) // date : 2005-09-10 // compile & link : gcc -o mon_routing_table mon_routing_table.c #include #include #include #include // buffer to hold the RTNETLINK request struct { struct nlmsghdr nl; struct rtmsg rt; char buf[8192]; } req; // variables used for // socket communications int fd; struct sockaddr_nl la; struct sockaddr_nl pa; struct msghdr msg; struct iovec iov; int rtn; // buffer to hold the RTNETLINK reply(ies) char buf[8192]; // RTNETLINK message pointers & lengths // used when processing messages struct nlmsghdr *nlp; int nll; struct rtmsg *rtp; int rtl; struct rtattr *rtap; void recv_reply() { char *p; // initialize the socket read buffer bzero(buf, sizeof(buf)); p = buf; nll = 0; // read from the socket until the NLMSG_DONE is // returned in the type of the RTNETLINK message // or if it was a monitoring socket while(1) { rtn = recv(fd, p, sizeof(buf) - nll, 0); nlp = (struct nlmsghdr *) p; if(nlp->nlmsg_type == NLMSG_DONE) break; // increment the buffer pointer to place // next message p += rtn; // increment the total size by the size of // the last received message nll += rtn; if((la.nl_groups & RTMGRP_IPV4_ROUTE) == RTMGRP_IPV4_ROUTE) break; } } void read_reply() { // string to hold content of the route // table (i.e. one entry) char dsts[24], gws[24], ifs[16], ms[24]; // outer loop: loops thru all the NETLINK // headers that also include the route entry // header nlp = (struct nlmsghdr *) buf; for(;NLMSG_OK(nlp, nll);nlp=NLMSG_NEXT(nlp, nll)) { // get route entry header rtp = (struct rtmsg *) NLMSG_DATA(nlp); // we are only concerned about the // main route table if(rtp->rtm_table != RT_TABLE_MAIN) continue; // init all the strings bzero(dsts, sizeof(dsts)); bzero(gws, sizeof(gws)); bzero(ifs, sizeof(ifs)); bzero(ms, sizeof(ms)); // inner loop: loop thru all the attributes of // one route entry rtap = (struct rtattr *) RTM_RTA(rtp); rtl = RTM_PAYLOAD(nlp); for(;RTA_OK(rtap, rtl);rtap=RTA_NEXT(rtap,rtl)) { switch(rtap->rta_type) { // destination IPv4 address case RTA_DST: inet_ntop(AF_INET, RTA_DATA(rtap), dsts, 24); break; // next hop IPv4 address case RTA_GATEWAY: inet_ntop(AF_INET, RTA_DATA(rtap), gws, 24); break; // unique ID associated with the network // interface case RTA_OIF: sprintf(ifs, "%d", *((int *) RTA_DATA(rtap))); default: break; } } sprintf(ms, "%d", rtp->rtm_dst_len); printf("dst %s/%s gw %s if %s\n", dsts, ms, gws, ifs); } } int main(int argc, char *argv[]) { // open socket fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); // setup local address & bind using // this address bzero(&la, sizeof(la)); la.nl_family = AF_NETLINK; la.nl_pid = getpid(); la.nl_groups = RTMGRP_IPV4_ROUTE | RTMGRP_NOTIFY; bind(fd, (struct sockaddr*) &la, sizeof(la)); // sub functions to create RTNETLINK message, // send over socket, reveive reply & process // message recv_reply(); read_reply(); // close socket close(fd); }