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EthUDP.c
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EthUDP.c
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/* EthUDP: used to create tunnel over ipv4/ipv6 network
by james@ustc.edu.cn 2009.04.02
*/
// kernel use auxdata to send vlan tag, we use auxdata to reconstructe vlan header
#define HAVE_PACKET_AUXDATA 1
// enable OPENSSL encrypt/decrypt support
#define ENABLE_OPENSSL 1
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <fcntl.h>
#include <unistd.h>
#include <syslog.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <time.h>
#include <net/if.h>
#include <linux/if_packet.h>
#include <linux/if_ether.h>
#include <linux/if_tun.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netdb.h>
#include <stdarg.h>
#include <errno.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>
#include <lz4.h>
#include <pcap.h>
#define MAXLEN 2048
#define MAX_PACKET_SIZE 9234 // Jumbo Frame
#define MAXFD 64
#define STATUS_BAD 0
#define STATUS_OK 1
#define MASTER 0
#define SLAVE 1
#define MODEE 0 // raw ether bridge mode
#define MODEI 1 // tap interface mode
#define MODEB 2 // bridge mode
#define MODET 3 // tcpdump full packet to remote
#define MODEU 4 // tcpdump udp packet to remote
//#define DEBUGPINGPONG 1
//#define DEBUGSSL 1
// ip & brctl command
#define IPCMD "/sbin/ip"
#define BRIDGECMD "/usr/sbin/brctl"
#define XOR 1
#ifdef ENABLE_OPENSSL
#include <openssl/evp.h>
#define AES_128 2
#define AES_192 3
#define AES_256 3
#else
#define EVP_MAX_BLOCK_LENGTH 0
#endif
#define max(a,b) ((a) > (b) ? (a) : (b))
#ifdef HAVE_PACKET_AUXDATA
#define VLAN_TAG_LEN 4
struct vlan_tag {
u_int16_t vlan_tpid; /* ETH_P_8021Q */
u_int16_t vlan_tci; /* VLAN TCI */
};
#endif
u_int16_t ETHP8021Q; // 0x8100 in network order
struct _EtherHeader {
uint16_t destMAC1;
uint32_t destMAC2;
uint16_t srcMAC1;
uint32_t srcMAC2;
uint32_t VLANTag;
uint16_t type;
int32_t payload;
} __attribute__ ((packed));
typedef struct _EtherHeader EtherPacket;
struct packet_buf {
time_t rcvt; // recv time, 0 if not valid
int len; // buf len
unsigned char *buf; // packet header is 8 bytes: UDPFRG+seq
};
#define MAXPKTS 65536
struct packet_buf packet_bufs[MAXPKTS]; // buf[0] & buf[1] is pair, store the orignal big UDP packets
int daemon_proc; /* set nonzero by daemon_init() */
volatile int debug = 0;
int mode = -1; // 0 eth bridge, 1 interface, 2 bridge
int mtu = 0;
int udp_frg_seq = 0;
int master_slave = 0;
int read_only = 0, write_only = 0;
int fixmss = 0;
int nopromisc = 0;
int loopback_check = 0;
int packet_len = 1500;
char name[MAXLEN];
char run_cmd[MAXLEN];
char dev_name[MAXLEN];
int run_seconds = 0;
int32_t ifindex;
char mypassword[MAXLEN];
int enc_algorithm;
unsigned char enc_key[MAXLEN];
#ifdef ENABLE_OPENSSL
unsigned char enc_iv[EVP_MAX_IV_LENGTH];
#endif
int enc_key_len = 0;
int fdudp[2], fdraw;
int nat[2];
pcap_t *pcap_handle;
int lz4 = 0;
volatile long long udp_total = 0;
volatile long long compress_overhead = 0;
volatile long long compress_save = 0;
volatile long long encrypt_overhead = 0;
#define LZ4_SPACE 128
int vlan_map = 0;
int my_vlan[4096];
int remote_vlan[4096];
volatile struct sockaddr_storage local_addr[2];
volatile struct sockaddr_storage cmd_remote_addr[2];
volatile struct sockaddr_storage remote_addr[2];
volatile unsigned long myticket, last_pong[2]; // myticket inc 1 every 1 second after start
volatile unsigned long ping_send[2], ping_recv[2], pong_send[2], pong_recv[2];
volatile unsigned long raw_send_pkt, raw_send_byte, raw_recv_pkt, raw_recv_byte;
volatile unsigned long udp_send_pkt[2], udp_send_byte[2], udp_recv_pkt[2], udp_recv_byte[2];
volatile unsigned long udp_send_err[2], raw_send_err;
volatile int master_status = STATUS_BAD;
volatile int slave_status = STATUS_BAD;
volatile int current_remote = MASTER;
volatile int got_signal = 1;
void sig_handler_hup(int signo)
{
got_signal = 1;
}
void sig_handler_usr1(int signo)
{
udp_total = compress_overhead = compress_save = encrypt_overhead = 0;
raw_send_pkt = raw_send_byte = raw_recv_pkt = raw_recv_byte = 0;
udp_send_pkt[0] = udp_send_byte[0] = udp_recv_pkt[0] = udp_recv_byte[0] = 0;
udp_send_pkt[1] = udp_send_byte[1] = udp_recv_pkt[1] = udp_recv_byte[1] = 0;
}
void err_doit(int errnoflag, int level, const char *fmt, va_list ap)
{
int errno_save, n;
char buf[MAXLEN];
errno_save = errno; /* value caller might want printed */
vsnprintf(buf, sizeof(buf), fmt, ap); /* this is safe */
n = strlen(buf);
if (errnoflag)
snprintf(buf + n, sizeof(buf) - n, ": %s", strerror(errno_save));
strcat(buf, "\n");
if (daemon_proc) {
if (name[0])
syslog(level, "%s: %s", name, buf);
else
syslog(level, "%s", buf);
} else {
fflush(stdout); /* in case stdout and stderr are the same */
if (name[0]) {
fputs(name, stderr);
fputs(": ", stderr);
}
fputs(buf, stderr);
fflush(stderr);
}
return;
}
void err_msg(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
err_doit(0, LOG_INFO, fmt, ap);
va_end(ap);
return;
}
void Debug(const char *fmt, ...)
{
va_list ap;
if (debug) {
va_start(ap, fmt);
err_doit(0, LOG_INFO, fmt, ap);
va_end(ap);
}
return;
}
void err_quit(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
err_doit(0, LOG_ERR, fmt, ap);
va_end(ap);
exit(1);
}
void err_sys(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
err_doit(1, LOG_ERR, fmt, ap);
va_end(ap);
exit(1);
}
void daemon_init(const char *pname, int facility)
{
int i;
pid_t pid;
if ((pid = fork()) != 0)
exit(0); /* parent terminates */
/* 41st child continues */
setsid(); /* become session leader */
signal(SIGHUP, SIG_IGN);
if ((pid = fork()) != 0)
exit(0); /* 1st child terminates */
/* 42nd child continues */
daemon_proc = 1; /* for our err_XXX() functions */
umask(0); /* clear our file mode creation mask */
for (i = 0; i < MAXFD; i++)
close(i);
openlog(pname, LOG_PID, facility);
}
int udp_server(const char *host, const char *serv, socklen_t * addrlenp, int index)
{
int sockfd, n;
int on = 1;
struct addrinfo hints, *res, *ressave;
bzero(&hints, sizeof(struct addrinfo));
hints.ai_flags = AI_PASSIVE;
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
if ((n = getaddrinfo(host, serv, &hints, &res)) != 0)
err_quit("udp_server error for %s, %s", host, serv);
ressave = res;
do {
sockfd = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
if (sockfd < 0)
continue; /* error, try next one */
memcpy((void *)&(local_addr[index]), res->ai_addr, res->ai_addrlen);
setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, 1);
if (bind(sockfd, res->ai_addr, res->ai_addrlen) == 0)
break; /* success */
close(sockfd); /* bind error, close and try next one */
}
while ((res = res->ai_next) != NULL);
if (res == NULL) /* errno from final socket() or bind() */
err_sys("udp_server error for %s, %s", host, serv);
if (addrlenp)
*addrlenp = res->ai_addrlen; /* return size of protocol address */
freeaddrinfo(ressave);
return (sockfd);
}
int udp_xconnect(char *lhost, char *lserv, char *rhost, char *rserv, int index)
{
int sockfd, n;
struct addrinfo hints, *res, *ressave;
sockfd = udp_server(lhost, lserv, NULL, index);
n = 10 * 1024 * 1024;
setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &n, sizeof(n));
if (debug) {
socklen_t ln;
if (getsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, &n, &ln) == 0)
Debug("UDP socket RCVBUF setting to %d\n", n);
}
// set IP_MTU_DISCOVER, otherwise UDP has DFbit set
n = 0;
if (setsockopt(sockfd, IPPROTO_IP, IP_MTU_DISCOVER, &n, sizeof(n)) != 0)
err_msg("udp_xeonnect setsockopt returned error, errno %d\n", errno);
bzero(&hints, sizeof(struct addrinfo));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
if ((n = getaddrinfo(rhost, rserv, &hints, &res)) != 0)
err_quit("udp_xconnect error for %s, %s", rhost, rserv);
ressave = res;
do {
void *raddr;
if (res->ai_family == AF_INET) { // IPv4
struct sockaddr_in *ipv4 = (struct sockaddr_in *)res->ai_addr;
raddr = &(ipv4->sin_addr);
if ((memcmp(raddr, "\0\0\0\0", 4) == 0) || (ipv4->sin_port == 0)) {
Debug("nat = 1");
nat[index] = 1;
memcpy((void *)&(cmd_remote_addr[index]), res->ai_addr, res->ai_addrlen);
freeaddrinfo(ressave);
return sockfd;
}
} else { // IPv6
struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)res->ai_addr;
raddr = &(ipv6->sin6_addr);
if ((memcmp(raddr, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 16) == 0) || (ipv6->sin6_port == 0)) {
Debug("nat = 1");
nat[index] = 1;
memcpy((void *)&(cmd_remote_addr[index]), res->ai_addr, res->ai_addrlen);
freeaddrinfo(ressave);
return sockfd;
}
}
if (connect(sockfd, res->ai_addr, res->ai_addrlen) == 0) {
memcpy((void *)&(cmd_remote_addr[index]), res->ai_addr, res->ai_addrlen);
memcpy((void *)&(remote_addr[index]), res->ai_addr, res->ai_addrlen);
break; /* success */
}
}
while ((res = res->ai_next) != NULL);
if (res == NULL) /* errno set from final connect() */
err_sys("udp_xconnect error for %s, %s", rhost, rserv);
freeaddrinfo(ressave);
return (sockfd);
}
/**
* Open a rawsocket for the network interface
*/
int32_t open_rawsocket(char *ifname, int32_t * rifindex)
{
unsigned char buf[MAX_PACKET_SIZE];
int32_t ifindex;
struct ifreq ifr;
struct sockaddr_ll sll;
int n;
int32_t fd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
if (fd == -1)
err_sys("socket %s - ", ifname);
// get interface index
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
if (ioctl(fd, SIOCGIFINDEX, &ifr) == -1)
err_sys("SIOCGIFINDEX %s - ", ifname);
ifindex = ifr.ifr_ifindex;
*rifindex = ifindex;
if (!nopromisc) { // set promiscuous mode
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
ioctl(fd, SIOCGIFFLAGS, &ifr);
ifr.ifr_flags |= IFF_PROMISC;
ioctl(fd, SIOCSIFFLAGS, &ifr);
}
memset(&sll, 0xff, sizeof(sll));
sll.sll_family = AF_PACKET;
sll.sll_protocol = htons(ETH_P_ALL);
sll.sll_ifindex = ifindex;
if (bind(fd, (struct sockaddr *)&sll, sizeof(sll)) == -1)
err_sys("bind %s - ", ifname);
/* flush all received packets.
*
* raw-socket receives packets from all interfaces
* when the socket is not bound to an interface
*/
int32_t i, l = 0;
do {
fd_set fds;
struct timeval t;
FD_ZERO(&fds);
FD_SET(fd, &fds);
memset(&t, 0, sizeof(t));
i = select(FD_SETSIZE, &fds, NULL, NULL, &t);
if (i > 0) {
recv(fd, buf, i, 0);
l++;
};
Debug("interface %d flushed %d packets", ifindex, l);
}
while (i > 0);
/* Enable auxillary data if supported and reserve room for
* reconstructing VLAN headers. */
#ifdef HAVE_PACKET_AUXDATA
int val = 1;
if (setsockopt(fd, SOL_PACKET, PACKET_AUXDATA, &val, sizeof(val)) == -1 && errno != ENOPROTOOPT) {
err_sys("setsockopt(packet_auxdata): %s", strerror(errno));
}
#endif /* HAVE_PACKET_AUXDATA */
Debug("%s opened (fd=%d interface=%d)", ifname, fd, ifindex);
n = 10 * 1024 * 1024;
setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &n, sizeof(n));
if (debug) {
socklen_t ln;
if (getsockopt(fd, SOL_SOCKET, SO_RCVBUF, &n, &ln) == 0) {
Debug("RAW socket RCVBUF setting to %d", n);
}
}
return fd;
}
int xor_encrypt(u_int8_t * buf, int n, u_int8_t * nbuf)
{
int i;
for (i = 0; i < n; i++)
nbuf[i] = buf[i] ^ enc_key[i % enc_key_len];
return n;
}
#ifdef ENABLE_OPENSSL
int openssl_encrypt(u_int8_t * buf, int len, u_int8_t * nbuf)
{
EVP_CIPHER_CTX *ctx;
int outlen1, outlen2;
#ifdef DEBUGSSL
Debug("aes encrypt len=%d", len);
#endif
ctx = EVP_CIPHER_CTX_new();
if (enc_algorithm == AES_128)
EVP_EncryptInit(ctx, EVP_aes_128_cbc(), enc_key, enc_iv);
else if (enc_algorithm == AES_192)
EVP_EncryptInit(ctx, EVP_aes_192_cbc(), enc_key, enc_iv);
else if (enc_algorithm == AES_256)
EVP_EncryptInit(ctx, EVP_aes_256_cbc(), enc_key, enc_iv);
EVP_EncryptUpdate(ctx, nbuf, &outlen1, buf, len);
EVP_EncryptFinal(ctx, nbuf + outlen1, &outlen2);
len = outlen1 + outlen2;
#ifdef DEBUGSSL
Debug("after aes encrypt len=%d", len);
#endif
EVP_CIPHER_CTX_free(ctx);
return len;
}
int openssl_decrypt(u_int8_t * buf, int len, u_int8_t * nbuf)
{
EVP_CIPHER_CTX *ctx;
int outlen1, outlen2;
#ifdef DEBUGSSL
Debug("aes decrypt len=%d", len);
#endif
ctx = EVP_CIPHER_CTX_new();
if (enc_algorithm == AES_128)
EVP_DecryptInit(ctx, EVP_aes_128_cbc(), enc_key, enc_iv);
else if (enc_algorithm == AES_192)
EVP_DecryptInit(ctx, EVP_aes_192_cbc(), enc_key, enc_iv);
else if (enc_algorithm == AES_256)
EVP_DecryptInit(ctx, EVP_aes_256_cbc(), enc_key, enc_iv);
if (EVP_DecryptUpdate(ctx, nbuf, &outlen1, buf, len) != 1 || EVP_DecryptFinal(ctx, nbuf + outlen1, &outlen2) != 1)
len = 0;
else
len = outlen1 + outlen2;
#ifdef DEBUGSSL
Debug("after aes decrypt len=%d", len);
#endif
EVP_CIPHER_CTX_free(ctx);
return len;
}
#endif
int do_encrypt(u_int8_t * buf, int len, u_int8_t * nbuf)
{
u_int8_t lzbuf[MAX_PACKET_SIZE + LZ4_SPACE];
int nlen;
udp_total += len;
if (lz4 > 0) {
nlen = LZ4_compress_fast((char *)buf, (char *)lzbuf, len, len + LZ4_SPACE, lz4);
if (nlen <= 0) {
err_msg("lz4 compress error");
return 0;
}
if (debug)
Debug("compress %d-->%d save %d byte", len, nlen, len - nlen);
if (nlen < len) { // compressed
lzbuf[nlen] = 0xff; // 0xff means compressed data
nlen++;
compress_save += len - nlen;
len = nlen;
buf = lzbuf;
} else {
buf[len] = 0xaa; // 0xaa means not compressed data
compress_overhead++;
len++;
if (debug)
Debug("not compressed %d", len);
}
}
if (enc_key_len <= 0) {
memcpy(nbuf, buf, len);
return len;
}
if (enc_algorithm == XOR)
nlen = xor_encrypt(buf, len, nbuf);
#ifdef ENABLE_OPENSSL
else if ((enc_algorithm == AES_128)
|| (enc_algorithm == AES_192)
|| (enc_algorithm == AES_256))
nlen = openssl_encrypt(buf, len, nbuf);
#endif
else
return 0;
if (debug)
Debug("encrypt_overhead %d", nlen - len);
encrypt_overhead += nlen - len;
return nlen;
}
int do_decrypt(u_int8_t * buf, int len, u_int8_t * nbuf)
{
u_int8_t lzbuf[MAX_PACKET_SIZE + LZ4_SPACE];
if (enc_key_len > 0) {
if (enc_algorithm == XOR) {
len = xor_encrypt(buf, len, lzbuf);
buf = lzbuf;
}
#ifdef ENABLE_OPENSSL
else if ((enc_algorithm == AES_128)
|| (enc_algorithm == AES_192)
|| (enc_algorithm == AES_256)) {
len = openssl_decrypt(buf, len, lzbuf);
buf = lzbuf;
}
#endif
}
if ((lz4 > 0) && (len > 0)) {
len--;
if (buf[len] == 0xaa) { // not compressed data
if (debug)
Debug("decompress not compressed data %d", len);
memcpy(nbuf, buf, len);
} else if (buf[len] == 0xff) { // compressed data
int nlen;
nlen = LZ4_decompress_safe((char *)buf, (char *)nbuf, len, MAX_PACKET_SIZE + LZ4_SPACE);
if (nlen < 0) {
err_msg("lz4 decompress error");
return 0;
}
if (debug)
Debug("decompress %d-->%d", len, nlen);
len = nlen;
} else {
err_msg("len %d last byte error 0x%02X", len, buf[len]);
return 0;
}
} else
memcpy(nbuf, buf, len);
return len;
}
char *stamp(void)
{
static char st_buf[200];
struct timeval tv;
struct timezone tz;
struct tm *tm;
gettimeofday(&tv, &tz);
tm = localtime(&tv.tv_sec);
snprintf(st_buf, 200, "%02d%02d %02d:%02d:%02d.%06ld", tm->tm_mon + 1, tm->tm_mday, tm->tm_hour, tm->tm_min, tm->tm_sec, tv.tv_usec);
return st_buf;
}
void printPacket(EtherPacket * packet, ssize_t packetSize, char *message)
{
printf("%s ", stamp());
if ((ntohl(packet->VLANTag) >> 16) == 0x8100) // VLAN tag
printf("%s #%04x (VLAN %d) from %04x%08x to %04x%08x, len=%d\n",
message, ntohs(packet->type),
ntohl(packet->VLANTag) & 0xFFF, ntohs(packet->srcMAC1),
ntohl(packet->srcMAC2), ntohs(packet->destMAC1), ntohl(packet->destMAC2), (int)packetSize);
else
printf("%s #%04x (no VLAN) from %04x%08x to %04x%08x, len=%d\n",
message, ntohl(packet->VLANTag) >> 16,
ntohs(packet->srcMAC1), ntohl(packet->srcMAC2), ntohs(packet->destMAC1), ntohl(packet->destMAC2), (int)packetSize);
fflush(stdout);
}
// function from http://www.bloof.de/tcp_checksumming, thanks to crunsh
u_int16_t tcp_sum_calc(u_int16_t len_tcp, u_int16_t src_addr[], u_int16_t dest_addr[], u_int16_t buff[])
{
u_int16_t prot_tcp = 6;
u_int32_t sum = 0;
int nleft = len_tcp;
u_int16_t *w = buff;
/* calculate the checksum for the tcp header and payload */
while (nleft > 1) {
sum += *w++;
nleft -= 2;
}
/* if nleft is 1 there ist still on byte left. We add a padding byte (0xFF) to build a 16bit word */
if (nleft > 0)
sum += *w & ntohs(0xFF00); /* Thanks to Dalton */
/* add the pseudo header */
sum += src_addr[0];
sum += src_addr[1];
sum += dest_addr[0];
sum += dest_addr[1];
sum += htons(len_tcp);
sum += htons(prot_tcp);
// keep only the last 16 bits of the 32 bit calculated sum and add the carries
sum = (sum >> 16) + (sum & 0xFFFF);
sum += (sum >> 16);
// Take the one's complement of sum
sum = ~sum;
return ((u_int16_t) sum);
}
u_int16_t tcp_sum_calc_v6(u_int16_t len_tcp, u_int16_t src_addr[], u_int16_t dest_addr[], u_int16_t buff[])
{
u_int16_t prot_tcp = 6;
u_int32_t sum = 0;
int nleft = len_tcp;
u_int16_t *w = buff;
/* calculate the checksum for the tcp header and payload */
while (nleft > 1) {
sum += *w++;
nleft -= 2;
}
/* if nleft is 1 there ist still on byte left. We add a padding byte (0xFF) to build a 16bit word */
if (nleft > 0)
sum += *w & ntohs(0xFF00); /* Thanks to Dalton */
/* add the pseudo header */
int i;
for (i = 0; i < 8; i++)
sum = sum + src_addr[i] + dest_addr[i];
sum += htons(len_tcp); // why using 32bit len_tcp
sum += htons(prot_tcp);
// keep only the last 16 bits of the 32 bit calculated sum and add the carries
sum = (sum >> 16) + (sum & 0xFFFF);
sum += (sum >> 16);
// Take the one's complement of sum
sum = ~sum;
return ((u_int16_t) sum);
}
static unsigned int optlen(const u_int8_t * opt, unsigned int offset)
{
/* Beware zero-length options: make finite progress */
if (opt[offset] <= TCPOPT_NOP || opt[offset + 1] == 0)
return 1;
else
return opt[offset + 1];
}
void fix_mss(u_int8_t * buf, int len, int index)
{
u_int8_t *packet;
int i;
if (len < 54)
return;
packet = buf + 12; // skip ethernet dst & src addr
len -= 12;
if ((packet[0] == 0x81) && (packet[1] == 0x00)) { // skip 802.1Q tag 0x8100
packet += 4;
len -= 4;
}
if ((packet[0] == 0x08) && (packet[1] == 0x00)) { // IPv4 packet 0x0800
packet += 2;
len -= 2;
struct iphdr *ip = (struct iphdr *)packet;
if (ip->version != 4)
return; // check ipv4
if (ntohs(ip->frag_off) & 0x1fff)
return; // not the first fragment
if (ip->protocol != IPPROTO_TCP)
return; // not tcp packet
if (ntohs(ip->tot_len) > len)
return; // tot_len should < len
struct tcphdr *tcph = (struct tcphdr *)(packet + ip->ihl * 4);
if (!tcph->syn)
return;
if (debug)
Debug("fixmss ipv4 tcp syn");
u_int8_t *opt = (u_int8_t *) tcph;
for (i = sizeof(struct tcphdr); i < tcph->doff * 4; i += optlen(opt, i)) {
if (opt[i] == 2 && tcph->doff * 4 - i >= 4 && // TCP_MSS
opt[i + 1] == 4) {
u_int16_t newmss = fixmss, oldmss;
oldmss = (opt[i + 2] << 8) | opt[i + 3];
/* Never increase MSS, even when setting it, as
* doing so results in problems for hosts that rely
* on MSS being set correctly.
*/
if (oldmss <= newmss)
return;
if (debug)
Debug("change inner v4 tcp mss from %d to %d", oldmss, newmss);
opt[i + 2] = (newmss & 0xff00) >> 8;
opt[i + 3] = newmss & 0x00ff;
tcph->check = 0; /* Checksum field has to be set to 0 before checksumming */
tcph->check = (u_int16_t)
tcp_sum_calc((u_int16_t)
(ntohs(ip->tot_len) - ip->ihl * 4), (u_int16_t *) & ip->saddr, (u_int16_t *) & ip->daddr, (u_int16_t *) tcph);
return;
}
}
} else if ((packet[0] == 0x86) && (packet[1] == 0xdd)) { // IPv6 packet, 0x86dd
packet += 2;
len -= 2;
struct ip6_hdr *ip6 = (struct ip6_hdr *)packet;
if ((ip6->ip6_vfc & 0xf0) != 0x60)
return; // check ipv6
if (ip6->ip6_nxt != IPPROTO_TCP)
return; // not tcp packet
if (ntohs(ip6->ip6_plen) > len)
return; // tot_len should < len
struct tcphdr *tcph = (struct tcphdr *)(packet + 40);
if (!tcph->syn)
return;
if (debug)
Debug("fixmss ipv6 tcp syn");
u_int8_t *opt = (u_int8_t *) tcph;
for (i = sizeof(struct tcphdr); i < tcph->doff * 4; i += optlen(opt, i)) {
if (opt[i] == 2 && tcph->doff * 4 - i >= 4 && // TCP_MSS
opt[i + 1] == 4) {
u_int16_t newmss = fixmss, oldmss;
oldmss = (opt[i + 2] << 8) | opt[i + 3];
/* Never increase MSS, even when setting it, as
* doing so results in problems for hosts that rely
* on MSS being set correctly.
*/
if (oldmss <= newmss)
return;
if (debug)
Debug("change inner v6 tcp mss from %d to %d", oldmss, newmss);
opt[i + 2] = (newmss & 0xff00) >> 8;
opt[i + 3] = newmss & 0x00ff;
tcph->check = 0; /* Checksum field has to be set to 0 before checksumming */
tcph->check = (u_int16_t) tcp_sum_calc_v6((u_int16_t)
ntohs(ip6->ip6_plen),
(u_int16_t *) & ip6->ip6_src, (u_int16_t *) & ip6->ip6_dst, (u_int16_t *)
tcph);
return;
}
}
}
}
/* return 1 if packet will cause loopback, DSTIP or SRCIP == remote address && PROTO == UDP
*/
int do_loopback_check(u_int8_t * buf, int len)
{
u_int8_t *packet;
if (len < 14) // MAC(12)+Proto(2)+IP(20)
return 0;
packet = buf + 12; // skip ethernet dst & src addr
len -= 12;
if ((packet[0] == 0x81) && (packet[1] == 0x00)) { // skip 802.1Q tag 0x8100
packet += 4;
len -= 4;
}
if ((packet[0] == 0x08) && (packet[1] == 0x00)) { // IPv4 packet 0x0800
packet += 2;
len -= 2;
if (len < 20) // IP header len is 20
return 0;
struct iphdr *ip = (struct iphdr *)packet;
if (ip->version != 4)
return 0; // not ipv4
if (ip->protocol != IPPROTO_UDP)
return 0; // not udp packet
struct sockaddr_in *r = (struct sockaddr_in *)(&remote_addr[MASTER]);
if (ip->saddr == r->sin_addr.s_addr) {
if (debug)
Debug("master remote ipaddr == src addr, loopback");
return 1;
} else if (ip->daddr == r->sin_addr.s_addr) {
if (debug)
Debug("master remote ipaddr == dst addr, loopback");
return 1;
}
if (master_slave) {
r = (struct sockaddr_in *)(&remote_addr[SLAVE]);
if (ip->saddr == r->sin_addr.s_addr) {
if (debug)
Debug("slave remote ipaddr == src addr, loopback");
return 1;
} else if (ip->daddr == r->sin_addr.s_addr) {
if (debug)
Debug("slave remote ipaddr == dst addr, loopback");
return 1;
}
}
} else if ((packet[0] == 0x86) && (packet[1] == 0xdd)) { // IPv6 packet, 0x86dd
packet += 2;
len -= 2;
if (len < 40) // IPv6 header len is 40
return 0;
struct ip6_hdr *ip6 = (struct ip6_hdr *)packet;
if ((ip6->ip6_vfc & 0xf0) != 0x60)
return 0; // not ipv6
if (ip6->ip6_nxt != IPPROTO_UDP)
return 0; // not udp packet
struct sockaddr_in6 *r = (struct sockaddr_in6 *)&remote_addr[MASTER];
if (memcmp(&ip6->ip6_src, &r->sin6_addr, 16) == 0) {
if (debug)
Debug("master remote ip6_addr == src ip6 addr, loopback");
return 1;
} else if (memcmp(&ip6->ip6_dst, &r->sin6_addr, 16) == 0) {
if (debug)
Debug("master remote ip6_addr == dst ip6 addr, loopback");
return 1;
}
if (master_slave) {
r = (struct sockaddr_in6 *)&remote_addr[SLAVE];
if (memcmp(&ip6->ip6_src, &r->sin6_addr, 16) == 0) {
if (debug)
Debug("slave remote ip6_addr == src ip6 addr, loopback");
return 1;
} else if (memcmp(&ip6->ip6_dst, &r->sin6_addr, 16) == 0) {
if (debug)
Debug("slave remote ip6_addr == dst ip6 addr, loopback");
return 1;
}
}
}
return 0;
}
void send_udp_to_remote(u_int8_t * buf, int len, int index);
void send_frag_udp(u_int8_t * buf, int len, int index)
{
unsigned char newbuf[MAX_PACKET_SIZE];
if (len >= 2000) // should not go here
return;
if (len <= 1000) // should not go here
return;
memcpy(newbuf, "UDPFRG", 6);
newbuf[6] = (udp_frg_seq >> 8) & 0xff;
newbuf[7] = udp_frg_seq & 0xff;
memcpy(newbuf + 8, buf, 1000);
if (debug)
Debug("send frag %d, len=1000, total_len=%d", udp_frg_seq, len);
send_udp_to_remote(newbuf, 1008, index);
udp_frg_seq++;
if (udp_frg_seq >= MAXPKTS)
udp_frg_seq = 0;
newbuf[6] = (udp_frg_seq >> 8) & 0xff;
newbuf[7] = udp_frg_seq & 0xff;
memcpy(newbuf + 8, buf + 1000, len - 1000);
if (debug)
Debug("send frag %d, len=%d, total_len=%d", udp_frg_seq, len - 1000, len);
send_udp_to_remote(newbuf, 8 + len - 1000, index);
udp_frg_seq++;
if (udp_frg_seq >= MAXPKTS)
udp_frg_seq = 0;
}
void send_udp_to_remote(u_int8_t * buf, int len, int index) // send udp packet to remote
{
if ((mtu > 0) && (len > mtu - 28))
return send_frag_udp(buf, len, index);
if (nat[index]) {
char rip[200];
if (remote_addr[index].ss_family == AF_INET) {
struct sockaddr_in *r = (struct sockaddr_in *)(&remote_addr[index]);
if (debug)
Debug("nat mode: send len %d to %s:%d", len, inet_ntop(r->sin_family, (void *)&r->sin_addr, rip, 200), ntohs(r->sin_port));
if (r->sin_port) {
sendto(fdudp[index], buf, len, 0, (struct sockaddr *)&remote_addr[index], sizeof(struct sockaddr_storage));
udp_send_pkt[index]++;
udp_send_byte[index] += len;
}
} else if (remote_addr[index].ss_family == AF_INET6) {
struct sockaddr_in6 *r = (struct sockaddr_in6 *)&remote_addr[index];
if (debug)
Debug("nat mode: send len %d to [%s]:%d", len, inet_ntop(r->sin6_family, (void *)&r->sin6_addr, rip, 200), ntohs(r->sin6_port));
if (r->sin6_port) {
sendto(fdudp[index], buf, len, 0, (struct sockaddr *)&remote_addr[index], sizeof(struct sockaddr_storage));
udp_send_pkt[index]++;
udp_send_byte[index] += len;
}
}
} else {
if (write(fdudp[index], buf, len) != len)
udp_send_err[index]++;
else {
udp_send_pkt[index]++;
udp_send_byte[index] += len;
}
}
}
void print_addrinfo(int index)
{
char localip[200];
char cmd_remoteip[200];
char remoteip[200];
if (local_addr[index].ss_family == AF_INET) {
struct sockaddr_in *r = (struct sockaddr_in *)(&local_addr[index]);
int lp, c_rp, rp;
lp = ntohs(r->sin_port);
inet_ntop(AF_INET, &r->sin_addr, localip, 200);
r = (struct sockaddr_in *)(&cmd_remote_addr[index]);
c_rp = ntohs(r->sin_port);
inet_ntop(AF_INET, &r->sin_addr, cmd_remoteip, 200);
r = (struct sockaddr_in *)(&remote_addr[index]);
rp = ntohs(r->sin_port);
inet_ntop(AF_INET, &r->sin_addr, remoteip, 200);
if (nat[index])
err_msg("%s: ST:%d %s:%d --> %s:%d(%s:%d)", index == 0 ? "MASTER" : " SLAVE", index == 0 ? master_status : slave_status, localip, lp,
remoteip, rp, cmd_remoteip, c_rp);
else
err_msg("%s: ST:%d %s:%d --> %s:%d", index == 0 ? "MASTER" : " SLAVE", index == 0 ? master_status : slave_status, localip, lp, remoteip,
rp);
} else if (local_addr[index].ss_family == AF_INET6) {
struct sockaddr_in6 *r = (struct sockaddr_in6 *)(&local_addr[index]);
int lp, c_rp, rp;