X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=greprotocol.cpp;fp=greprotocol.cpp;h=b826a521d7828c4e18421250f07c8a3ee8d09d9d;hb=7c67b21504e7758f4148386befc8cd80455a1a85;hp=0000000000000000000000000000000000000000;hpb=2b1c67c9a219ea85de7db4ada9364da3905e7b62;p=greproxy

diff --git a/greprotocol.cpp b/greprotocol.cpp
new file mode 100644
index 0000000..b826a52
--- /dev/null
+++ b/greprotocol.cpp
@@ -0,0 +1,112 @@
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include "greprotocol.h"
+#include "reorderer.h"
+
+using namespace std;
+
+struct gre_header {
+	uint8_t reserved0_hi : 4;
+	uint8_t has_seq : 1;
+	uint8_t has_key : 1;
+	uint8_t unused : 1;
+	uint8_t has_checksum : 1;
+
+	uint8_t version : 3;
+	uint8_t reserved0_lo: 5;
+
+	uint16_t protocol_type;
+};
+
+
+GREProtocol::GREProtocol(const in6_addr &src, const in6_addr &dst)
+	: seq(0)
+{
+	memset(&dstaddr, 0, sizeof(dstaddr));
+	dstaddr.sin6_family = AF_INET6;
+	dstaddr.sin6_addr = dst;
+
+	sock = socket(AF_INET6, SOCK_RAW, IPPROTO_GRE);
+	if (sock == -1) {
+		perror("socket");
+		exit(1);
+	}
+
+	sockaddr_in6 my_addr;
+	memset(&my_addr, 0, sizeof(my_addr));
+	my_addr.sin6_family = AF_INET6;
+	my_addr.sin6_addr = src;
+	if (::bind(sock, (sockaddr *)&my_addr, sizeof(my_addr)) == -1) {
+		perror("bind");
+		exit(1);
+	}
+}
+
+void GREProtocol::send_packet(uint16_t proto, const string &data)
+{
+	char buf[4096];
+	gre_header *gre = (gre_header *)buf;
+
+	memset(gre, 0, sizeof(*gre));
+	gre->has_seq = 1;
+	gre->version = 0;
+	gre->protocol_type = htons(proto);
+
+	char *ptr = buf + sizeof(*gre);
+	int seq_be = htonl(seq++);
+	memcpy(ptr, &seq_be, sizeof(seq_be));
+	ptr += sizeof(seq_be);
+
+	memcpy(ptr, data.data(), data.size());
+	
+	if (sendto(sock, buf, data.size() + sizeof(seq_be) + sizeof(*gre), 0, (sockaddr *)&dstaddr, sizeof(dstaddr)) == -1) {
+		perror("sendto");
+		return;
+	}
+}
+
+int GREProtocol::fd() const
+{
+	return sock;
+}
+
+void GREProtocol::read_packet(Reorderer *sender)
+{
+	struct sockaddr_storage addr;
+	socklen_t addrlen = sizeof(addr);
+	char buf[4096];
+	int ret = recvfrom(sock, buf, sizeof(buf), 0, (struct sockaddr *)&addr, &addrlen);
+	if (ret == -1) {
+		perror("recvfrom");
+		exit(1);
+	}
+	if (addr.ss_family != AF_INET6) {
+		return;
+	}
+	struct in6_addr *addr6 = &((struct sockaddr_in6 *)&addr)->sin6_addr;
+	if (memcmp(addr6, &dstaddr.sin6_addr, sizeof(*addr6)) != 0) {
+		// ignore
+		return;
+	}
+	gre_header* gre = (gre_header *)buf;
+
+	char* ptr = buf + sizeof(gre_header);
+	if (gre->has_checksum) {
+		ptr += 4;
+	}
+	if (gre->has_key) {
+		ptr += 4;
+	}
+	uint32_t seq;
+	if (gre->has_seq) {
+		seq = ntohl(*(uint32_t *)ptr);
+		ptr += 4;
+	}
+
+	//printf("gre packet: proto=%x\n", ntohs(gre->protocol_type));
+
+	sender->handle_packet(ntohs(gre->protocol_type), string(ptr, buf + ret), seq);
+}
+