7 #include <netinet/in.h>
10 #include <linux/if_tun.h>
19 uint8_t reserved0_hi : 4;
23 uint8_t has_checksum : 1;
26 uint8_t reserved0_lo: 5;
28 uint16_t protocol_type;
31 int tun_open(const char *name) {
34 int fd = open("/dev/net/tun", O_RDWR);
36 perror("/dev/net/tun");
40 memset(&ifr, 0, sizeof(ifr));
41 ifr.ifr_flags = IFF_TUN;
42 strncpy(ifr.ifr_name, name, IFNAMSIZ);
44 int err = ioctl(fd, TUNSETIFF, &ifr);
46 perror("ioctl(TUNSETIFF)");
53 in6_addr get_addr(const char *str) {
55 if (inet_pton(AF_INET6, str, &ret) != 1) {
56 fprintf(stderr, "Could not parse %s\n", str);
67 bool operator> (const GREPacket &other) const {
68 return seq > other.seq;
74 virtual void send_packet(uint16_t proto, const string &data) = 0;
77 class GRESender : public Sender {
79 GRESender(int sock, const in6_addr &dst);
80 virtual void send_packet(uint16_t proto, const string &data);
88 class TUNSender : public Sender {
91 virtual void send_packet(uint16_t proto, const string &data);
99 Reorderer(Sender* sender);
100 void handle_packet(uint16_t proto, const string& data, int seq);
103 void send_packet(uint16_t proto, const string &data, bool silence);
108 priority_queue<GREPacket, vector<GREPacket>, greater<GREPacket>> packet_buffer;
112 GRESender::GRESender(int sock, const in6_addr &dst)
115 memset(&dstaddr, 0, sizeof(dstaddr));
116 dstaddr.sin6_family = AF_INET6;
117 dstaddr.sin6_addr = dst;
120 void GRESender::send_packet(uint16_t proto, const string &data)
123 gre_header *gre = (gre_header *)buf;
125 memset(gre, 0, sizeof(*gre));
128 gre->protocol_type = htons(proto);
130 char *ptr = buf + sizeof(*gre);
131 int seq_be = htonl(seq++);
132 memcpy(ptr, &seq_be, sizeof(seq_be));
133 ptr += sizeof(seq_be);
135 memcpy(ptr, data.data(), data.size());
137 if (sendto(sock, buf, data.size() + sizeof(seq_be) + sizeof(*gre), 0, (sockaddr *)&dstaddr, sizeof(dstaddr)) == -1) {
143 TUNSender::TUNSender(int tunfd)
146 void TUNSender::send_packet(uint16_t proto, const string &data)
152 memcpy(ptr, &flags, sizeof(flags));
153 ptr += sizeof(flags);
155 proto = htons(proto);
156 memcpy(ptr, &proto, sizeof(proto));
157 ptr += sizeof(proto);
159 memcpy(ptr, data.data(), data.size());
161 int len = sizeof(flags) + sizeof(proto) + data.size();
162 if (write(tunfd, buf, len) != len) {
168 Reorderer::Reorderer(Sender* sender)
169 : sender(sender), last_seq(-1)
173 #define PACKET_BUFFER_SIZE 100
175 void Reorderer::handle_packet(uint16_t proto, const string& data, int seq)
177 bool silence = false;
178 if (packet_buffer.size() >= PACKET_BUFFER_SIZE) {
179 printf("Gave up waiting for packets [%d,%d>\n",
180 last_seq + 1, packet_buffer.top().seq);
182 last_seq = packet_buffer.top().seq - 1;
187 packet.proto = proto;
189 packet_buffer.push(packet);
191 while (!packet_buffer.empty() &&
192 (last_seq == -1 || packet_buffer.top().seq <= last_seq + 1)) {
193 int front_seq = packet_buffer.top().seq;
194 if (front_seq < last_seq + 1) {
195 printf("Duplicate packet or way out-of-order: seq=%d front_seq=%d\n",
196 front_seq, last_seq + 1);
200 //if (packet_buffer.size() > 1) {
201 // printf("seq=%d (REORDER %d)\n", front_seq, int(packet_buffer.size()));
203 // printf("seq=%d\n", front_seq);
205 const string &data = packet_buffer.top().data;
206 send_packet(packet_buffer.top().proto, data, silence);
208 last_seq = front_seq;
209 if (!silence && !packet_buffer.empty()) {
210 printf("Reordering with packet buffer size %d: seq=%d new_front_seq=%d\n", int(packet_buffer.size()), front_seq, packet_buffer.top().seq);
216 void Reorderer::send_packet(uint16_t proto, const string &data, bool silence)
218 if (data.size() == 1344) {
219 for (int i = 0; i < 7; ++i) {
220 const char *pkt = &data[i * 188 + 28];
221 int pid = (ntohl(*(uint32_t *)(pkt)) & 0x1fff00) >> 8;
226 int has_payload = pkt[3] & 0x10;
227 int cc = pkt[3] & 0xf;
229 int last_cc = ccs[pid];
230 if (!silence && cc != ((last_cc + 1) & 0xf)) {
231 printf("Pid %d discontinuity (expected %d, got %d)\n", pid, (last_cc + 1) & 0xf, cc);
237 sender->send_packet(proto, data);
240 void read_gre_packet(int gresock, const in6_addr &remoteaddr, Reorderer *sender)
242 struct sockaddr_storage addr;
243 socklen_t addrlen = sizeof(addr);
245 int ret = recvfrom(gresock, buf, sizeof(buf), 0, (struct sockaddr *)&addr, &addrlen);
250 if (addr.ss_family != AF_INET6) {
253 struct in6_addr *addr6 = &((struct sockaddr_in6 *)&addr)->sin6_addr;
254 if (memcmp(addr6, &remoteaddr, sizeof(*addr6)) != 0) {
258 gre_header* gre = (gre_header *)buf;
260 char* ptr = buf + sizeof(gre_header);
261 if (gre->has_checksum) {
269 seq = ntohl(*(uint32_t *)ptr);
273 //printf("gre packet: proto=%x\n", ntohs(gre->protocol_type));
275 sender->handle_packet(ntohs(gre->protocol_type), string(ptr, buf + ret), seq);
278 void read_tun_packet(int tunfd, Sender *sender)
281 int ret = read(tunfd, buf, sizeof(buf));
287 fprintf(stderr, "tunfd EOF\n");
292 uint16_t flags = *(uint16_t *)ptr;
294 uint16_t proto = ntohs(*(uint16_t *)ptr);
296 //fprintf(stderr, "tun packet: flags=%x proto=%x len=%d\n",
297 // flags, proto, ret - 4);
298 sender->send_packet(proto, string(ptr, buf + ret));
301 int main(int argc, char **argv)
303 int tunfd = tun_open("tungre");
304 int gresock = socket(AF_INET6, SOCK_RAW, IPPROTO_GRE);
310 sockaddr_in6 my_addr;
311 memset(&my_addr, 0, sizeof(my_addr));
312 my_addr.sin6_family = AF_INET6;
313 my_addr.sin6_addr = get_addr(argv[1]);
314 if (bind(gresock, (sockaddr *)&my_addr, sizeof(my_addr)) == -1) {
319 in6_addr remoteaddr = get_addr(argv[2]);
320 GRESender gre_sender(gresock, remoteaddr);
321 TUNSender tun_sender(tunfd);
323 Reorderer tun_reorderer(&tun_sender);
328 FD_SET(gresock, &fds);
330 int ret = select(1024, &fds, NULL, NULL, NULL);
336 if (FD_ISSET(gresock, &fds)) {
337 read_gre_packet(gresock, remoteaddr, &tun_reorderer);
339 if (FD_ISSET(tunfd, &fds)) {
340 read_tun_packet(tunfd, &gre_sender);