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Use siphash to select path

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Signed-off-by: Adrien Gallouët <adrien@gallouet.fr>
This commit is contained in:
Adrien Gallouët
2018-09-29 16:13:01 +00:00
parent 6719b19681
commit 56a3a751db
2 changed files with 86 additions and 10 deletions
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24
src/bind.c
View File

@@ -12,6 +12,8 @@
#include "../argz/argz.h"
#include "../mud/mud.h"
#include <sodium.h>
#ifndef O_CLOEXEC
#define O_CLOEXEC 0
#endif
@@ -151,6 +153,14 @@ gt_bind(int argc, char **argv)
int chacha = argz_is_set(bindz, "chacha");
int persist = argz_is_set(bindz, "persist");
if (sodium_init() == -1) {
gt_log("couldn't init sodium\n");
return 1;
}
unsigned char hashkey[crypto_shorthash_KEYBYTES];
crypto_shorthash_keygen(hashkey);
struct mud *mud = mud_create((struct sockaddr *)&bind_addr);
if (!mud) {
@@ -314,15 +324,21 @@ gt_bind(int argc, char **argv)
struct ip_common ic;
const int r = tun_read(tun_fd, buf, bufsize);
if (!ip_get_common(&ic, buf, r))
mud_send(mud, buf, r, ic.tc);
if (!ip_get_common(&ic, buf, r)) {
unsigned char hash[crypto_shorthash_BYTES];
crypto_shorthash(hash, (const unsigned char *)&ic, sizeof(ic), hashkey);
unsigned h;
memcpy(&h, hash, sizeof(h));
mud_send(mud, buf, r, (h << 8) | ic.tc);
}
}
if (FD_ISSET(mud_fd, &rfds)) {
struct ip_common ic;
const int r = mud_recv(mud, buf, bufsize);
if (!ip_get_common(&ic, buf, r))
if (ip_is_valid(buf, r))
tun_write(tun_fd, buf, r);
}

72
src/ip.h
View File

@@ -5,7 +5,26 @@
struct ip_common {
uint8_t tc;
uint8_t proto;
struct { // data are not reordered
union {
unsigned char v6[16];
struct {
unsigned char zero[10];
unsigned char ff[2];
unsigned char v4[4];
};
};
unsigned char port[2];
} src, dst;
};
static inline int
ip_read16(const uint8_t *src)
{
uint16_t ret = src[1];
ret |= ((uint16_t)src[0]) << 8;
return (int)ret;
}
static inline uint8_t
ip_get_version(const uint8_t *data)
@@ -14,11 +33,17 @@ ip_get_version(const uint8_t *data)
}
static inline int
ip_read16(const uint8_t *src)
ip_is_valid(const uint8_t *data, int size)
{
uint16_t ret = src[1];
ret |= ((uint16_t)src[0]) << 8;
return (int)ret;
if (size < 20)
return 0;
switch (ip_get_version(data)) {
case 4: return size == ip_read16(&data[2]);
case 6: return size == ip_read16(&data[4]) + 40;
}
return 0;
}
static inline int
@@ -31,11 +56,46 @@ ip_get_common(struct ip_common *ic, const uint8_t *data, int size)
case 4:
ic->tc = data[1];
ic->proto = data[9];
return size != ip_read16(&data[2]);
if (size == ip_read16(&data[2])) {
const int hdrsize = (data[0] & 0xF) << 2;
memset(ic->src.zero, 0, sizeof(ic->src.zero));
memset(ic->src.ff, 0xff, sizeof(ic->src.ff));
memcpy(ic->src.v4, &data[12], sizeof(ic->src.v4));
memset(ic->dst.zero, 0, sizeof(ic->dst.zero));
memset(ic->dst.ff, 0xff, sizeof(ic->dst.ff));
memcpy(ic->dst.v4, &data[16], sizeof(ic->dst.v4));
switch (ic->proto) {
case 6: // tcp
case 17: // udp
memcpy(ic->src.port, &data[hdrsize], sizeof(ic->src.port));
memcpy(ic->dst.port, &data[hdrsize + 2], sizeof(ic->dst.port));
break;
default:
memset(ic->src.port, 0, sizeof(ic->src.port));
memset(ic->dst.port, 0, sizeof(ic->dst.port));
}
return 0;
}
break;
case 6:
ic->tc = ((data[0] & 0xF) << 4) | (data[1] >> 4);
ic->proto = data[6];
return size != ip_read16(&data[4]) + 40;
if (size == ip_read16(&data[4]) + 40) {
memcpy(ic->src.v6, &data[8], sizeof(ic->src.v6));
memcpy(ic->dst.v6, &data[24], sizeof(ic->dst.v6));
switch (ic->proto) {
case 6: // tcp
case 17: // udp
memcpy(ic->src.port, &data[40], sizeof(ic->src.port));
memcpy(ic->dst.port, &data[42], sizeof(ic->dst.port));
break;
default:
memset(ic->src.port, 0, sizeof(ic->src.port));
memset(ic->dst.port, 0, sizeof(ic->dst.port));
}
return 0;
}
break;
}
return 1;