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-rw-r--r--src/checksum.c124
-rw-r--r--src/checksum.h54
-rw-r--r--src/client.c119
3 files changed, 230 insertions, 67 deletions
diff --git a/src/checksum.c b/src/checksum.c
new file mode 100644
index 0000000..300237d
--- /dev/null
+++ b/src/checksum.c
@@ -0,0 +1,124 @@
+/*
+ *
+ * INET An implementation of the TCP/IP protocol suite for the LINUX
+ * operating system. INET is implemented using the BSD Socket
+ * interface as the means of communication with the user level.
+ *
+ * IP/TCP/UDP checksumming routines
+ *
+ * Authors: Jorge Cwik, <jorge@laser.satlink.net>
+ * Arnt Gulbrandsen, <agulbra@nvg.unit.no>
+ * Tom May, <ftom@netcom.com>
+ * Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de>
+ * Lots of code moved from tcp.c and ip.c; see those files
+ * for more names.
+ *
+ * 03/02/96 Jes Sorensen, Andreas Schwab, Roman Hodek:
+ * Fixed some nasty bugs, causing some horrible crashes.
+ * A: At some points, the sum (%0) was used as
+ * length-counter instead of the length counter
+ * (%1). Thanks to Roman Hodek for pointing this out.
+ * B: GCC seems to mess up if one uses too many
+ * data-registers to hold input values and one tries to
+ * specify d0 and d1 as scratch registers. Letting gcc
+ * choose these registers itself solves the problem.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+/* Based on code from the Linux kernel. */
+
+#include <stdint.h>
+
+/* Revised by Kenneth Albanowski for m68knommu. Basic problem: unaligned access
+ kills, so most of the assembly has to go. */
+
+static inline unsigned short from32to16(unsigned int x)
+{
+ /* add up 16-bit and 16-bit for 16+c bit */
+ x = (x & 0xffff) + (x >> 16);
+ /* add up carry.. */
+ x = (x & 0xffff) + (x >> 16);
+ return x;
+}
+
+static unsigned int do_csum(const unsigned char *buff, int len)
+{
+ int odd;
+ unsigned int result = 0;
+
+ if (len <= 0)
+ goto out;
+ odd = 1 & (unsigned long) buff;
+ if (odd) {
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+ result += (*buff << 8);
+#else
+ result = *buff;
+#endif
+ len--;
+ buff++;
+ }
+ if (len >= 2) {
+ if (2 & (unsigned long) buff) {
+ result += *(unsigned short *) buff;
+ len -= 2;
+ buff += 2;
+ }
+ if (len >= 4) {
+ const unsigned char *end = buff + ((unsigned)len & ~3);
+ unsigned int carry = 0;
+ do {
+ unsigned int w = *(unsigned int *) buff;
+ buff += 4;
+ result += carry;
+ result += w;
+ carry = (w > result);
+ } while (buff < end);
+ result += carry;
+ result = (result & 0xffff) + (result >> 16);
+ }
+ if (len & 2) {
+ result += *(unsigned short *) buff;
+ buff += 2;
+ }
+ }
+ if (len & 1)
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+ result += *buff;
+#else
+ result += (*buff << 8);
+#endif
+ result = from32to16(result);
+ if (odd)
+ result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
+out:
+ return result;
+}
+
+/*
+ * computes the checksum of a memory block at buff, length len,
+ * and adds in "sum" (32-bit)
+ *
+ * returns a 32-bit number suitable for feeding into itself
+ * or csum_tcpudp_magic
+ *
+ * this function must be called with even lengths, except
+ * for the last fragment, which may be odd
+ *
+ * it's best to have buff aligned on a 32-bit boundary
+ */
+uint16_t csum_partial(const void *buff, int len, uint16_t wsum)
+{
+ uint16_t sum = wsum;
+ uint16_t result = do_csum(buff, len);
+
+ /* add in old sum, and carry.. */
+ result += sum;
+ if (sum > result)
+ result += 1;
+ return result;
+}
diff --git a/src/checksum.h b/src/checksum.h
index d9e6bda..f788ff1 100644
--- a/src/checksum.h
+++ b/src/checksum.h
@@ -1,27 +1,45 @@
+#include <stdarg.h>
#include <stdint.h>
+#include <stdlib.h>
-static inline uint16_t do_csum(const char *buf, unsigned size) {
- unsigned int sum = 0;
- unsigned int i;
+// based on code from RFCs 1071 and 1624
- for (i = 0; i < size - 1; i += 2)
- sum += *(uint16_t *)&buf[i];
-
- if (size & 1)
- sum += (uint8_t)buf[i];
+/*
+static inline uint16_t csum_update(const void *ptr, uint16_t new_value, uint16_t wsum) {
+ uint32_t sum = *(uint16_t *)ptr + (~ntohs(*(uint16_t *)&new_value) & 0xffff) + ntohs(wsum);
+ sum = (sum & 0xffff) + (sum >> 16);
+ return htons(sum + (sum >> 16));
+}
+static inline uint16_t fold_sum(uint32_t sum) {
while (sum >> 16)
- sum = (sum & 0xFFFF) + (sum >> 16);
-
- return ~sum;
+ sum = (sum & 0xffff) + (sum >> 16);
+ return sum;
}
-static inline uint16_t csum_partial(const void *buff, int len, uint16_t wsum) {
- unsigned int sum = (unsigned int)wsum;
- unsigned int result = do_csum(buff, len);
+static inline uint16_t do_csum(const void *ptr, size_t len) {
+ uint32_t sum = 0;
+
+ while (len > 1) {
+ sum += *(uint16_t *)ptr++;
+ len -= 2;
+ }
- result += sum;
- if (sum > result)
- result += 1;
- return result;
+ if (len > 0)
+ sum += *(uint8_t *)ptr;
+
+ return ~fold_sum(sum);
+}
+
+static inline uint16_t csum_partial(uint16_t sum, const void *ptr, size_t len, ...) {
+ va_list ap;
+ va_start(ap, len);
+ do {
+ sum = ~fold_sum(~sum + ~do_csum(ptr, len));
+ } while ((ptr = va_arg(ap, const void *)) && (len = va_arg(ap, size_t)));
+ va_end(ap);
+ return sum;
}
+*/
+
+uint16_t csum_partial(const void *buff, int len, uint16_t wsum);
diff --git a/src/client.c b/src/client.c
index 21f6217..23d5eac 100644
--- a/src/client.c
+++ b/src/client.c
@@ -1,3 +1,4 @@
+#include <assert.h>
#include <errno.h>
#include <ev.h>
#include <fcntl.h>
@@ -17,7 +18,19 @@
#include "client.h"
#include "uthash.h"
-#define PORTS_IN_INT sizeof(int) * CHAR_BIT
+#define PORTS_IN_INT (sizeof(int) * CHAR_BIT)
+
+struct c_data {
+ const char *r_host;
+ const char *r_port;
+ struct o_c_sock *o_socks_by_caddr;
+ struct o_c_rsock *o_rsocks;
+ struct sockaddr_storage pkt_addr;
+ int s_sock;
+ int i_sock;
+ socklen_t s_addrlen;
+ uint16_t csum_p;
+};
struct o_c_rsock {
struct sockaddr *r_addr;
@@ -27,8 +40,8 @@ struct o_c_rsock {
ev_io io_w;
UT_hash_handle hh;
int fd;
- uint16_t csum_a;
socklen_t r_addrlen;
+ uint16_t csum_p;
};
struct o_c_sock {
@@ -39,38 +52,27 @@ struct o_c_sock {
ev_timer tm_w;
UT_hash_handle hh_lp;
UT_hash_handle hh_ca;
+ uint16_t csum_p;
uint16_t seq_num;
in_port_t l_port;
uint8_t status;
int8_t syn_retries;
};
-struct c_data {
- const char *r_host;
- const char *r_port;
- struct o_c_sock *o_socks_by_caddr;
- struct o_c_rsock *o_rsocks;
- struct sockaddr_storage pkt_addr;
- socklen_t s_addrlen;
- int s_sock;
- int i_sock;
-};
-
static struct c_data *global_c_data;
static const uint8_t tcp_syn_retry_timeouts[] = { 3, 6, 12, 24, 0 };
static inline int check_resv_poff(unsigned int *used_ports, uint16_t poff) {
- if (used_ports[poff / PORTS_IN_INT] & (1 << poff % PORTS_IN_INT)) {
- used_ports[poff / PORTS_IN_INT] |= 1 << poff % PORTS_IN_INT;
- return poff;
- }
- return 0;
+ if (used_ports[poff / PORTS_IN_INT] & (1 << (poff % PORTS_IN_INT)))
+ return 0;
+ used_ports[poff / PORTS_IN_INT] |= 1 << (poff % PORTS_IN_INT);
+ return poff;
}
/* reserve a local TCP port (local addr, remote addr, remote port are usually
* fixed in the tuple) */
-static uint16_t reserve_port(unsigned int *used_ports) {
+static inline uint16_t reserve_port(unsigned int *used_ports) {
long r;
// randomly try 16 places
@@ -78,10 +80,10 @@ static uint16_t reserve_port(unsigned int *used_ports) {
r = random();
if (check_resv_poff(used_ports, r % 32768))
- return 32768 + r;
+ return 32768 + (r % 32768);
if (check_resv_poff(used_ports, (r >> 16) % 32768))
- return 32768 + (r >> 16);
+ return 32768 + ((r >> 16) % 32768);
}
// give up and go sequentially
@@ -285,50 +287,63 @@ static void cc_cb(struct ev_loop *loop, ev_io *w, int revents __attribute__((unu
}
}
-#define SIX_OR_FOUR(sa, six, four, neither) \
- (((struct sockaddr *)(sa))->sa_family == AF_INET6 ? (six) : ((struct sockaddr *)(sa))->sa_family == AF_INET ? (four) : abort(), neither)
-
-#define EXTRACT_IN_ADDR(sa) \
- SIX_OR_FOUR((struct sockaddr *)(sa), &(((struct sockaddr_in6 *)(sa))->sin6_addr), &(((struct sockaddr_in *)(sa))->sin_addr), NULL), \
- SIX_OR_FOUR((struct sockaddr *)(sa), sizeof(struct in6_addr), sizeof(in_addr_t), 0)
-
-static int c_rsock_init(struct o_c_sock *sock, struct addrinfo *res) {
- sock->rsock = malloc(sizeof(*sock->rsock));
- memset(&sock->rsock->used_ports, 0, sizeof(sock->rsock->used_ports));
- sock->rsock->r_addr = malloc(res->ai_addrlen);
+static inline struct o_c_rsock * c_rsock_init(struct addrinfo *res) {
+ struct o_c_rsock *rsock;
+ rsock = malloc(sizeof(*rsock));
+ memset(&rsock->used_ports, 0, sizeof(rsock->used_ports));
+ rsock->r_addr = malloc(res->ai_addrlen);
- memcpy(sock->rsock->r_addr, res->ai_addr, res->ai_addrlen);
- sock->rsock->r_addrlen = res->ai_addrlen;
+ memcpy(rsock->r_addr, res->ai_addr, res->ai_addrlen);
+ rsock->r_addrlen = res->ai_addrlen;
freeaddrinfo(res);
- sock->rsock->o_socks_by_lport = NULL;
+ rsock->o_socks_by_lport = NULL;
- sock->rsock->fd = socket(sock->rsock->r_addr->sa_family, SOCK_RAW, IPPROTO_TCP);
- if (!sock->rsock->fd) {
+ rsock->fd = socket(rsock->r_addr->sa_family, SOCK_RAW, IPPROTO_TCP);
+ if (!rsock->fd) {
perror("socket");
- return 0;
+ return NULL;
}
- if (connect(sock->rsock->fd, sock->rsock->r_addr, sock->rsock->r_addrlen) == -1) {
+ if (connect(rsock->fd, rsock->r_addr, rsock->r_addrlen) == -1) {
perror("connect");
- return 0;
+ return NULL;
}
- if (fcntl(sock->rsock->fd, F_SETFL, O_NONBLOCK) == -1) {
+ if (fcntl(rsock->fd, F_SETFL, O_NONBLOCK) == -1) {
perror("fcntl");
- return 0;
+ return NULL;
}
struct sockaddr_storage our_addr;
socklen_t our_addr_len = sizeof(our_addr);
- int r = getsockname(sock->rsock->fd, (struct sockaddr *)&our_addr, &our_addr_len);
+ int r = getsockname(rsock->fd, (struct sockaddr *)&our_addr, &our_addr_len);
if (r == -1) {
perror("getsockname");
- return 0;
+ return NULL;
}
- //sock->rsock->csum_a = csum_partial(EXTRACT_IN_ADDR(sock->rsock->r_addr), csum_partial(EXTRACT_IN_ADDR(&our_addr), 0));
+ char proto[] = { 0, IPPROTO_TCP };
+
+ if (((struct sockaddr *)rsock->r_addr)->sa_family != our_addr.ss_family)
+ abort();
+
+ switch (our_addr.ss_family) {
+ case AF_INET:
+ rsock->csum_p = csum_partial(&((struct sockaddr_in *)&our_addr)->sin_addr, sizeof(in_addr_t),
+ csum_partial(&((struct sockaddr_in *)rsock->r_addr)->sin_addr, sizeof(in_addr_t), 0));
+ break;
+ case AF_INET6:
+ rsock->csum_p = csum_partial(&((struct sockaddr_in6 *)&our_addr)->sin6_addr, sizeof(struct in6_addr),
+ csum_partial(&((struct sockaddr_in6 *)rsock->r_addr)->sin6_addr, sizeof(struct in6_addr), 0));
+ break;
+ default:
+ abort();
+ }
- return 1;
+ rsock->csum_p = csum_partial(&((struct sockaddr_in *)rsock->r_addr)->sin_port, sizeof(in_port_t),
+ csum_partial(proto, sizeof(proto), rsock->csum_p));
+
+ return rsock;
}
static void cs_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
@@ -368,7 +383,8 @@ static void cs_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
if (!sock->rsock) {
DBG("could not locate remote socket to host, initializing new raw socket");
- if (!c_rsock_init(sock, res)) {
+ sock->rsock = c_rsock_init(res);
+ if (!sock->rsock) {
ev_break(EV_A_ EVBREAK_ONE);
return;
}
@@ -382,6 +398,7 @@ static void cs_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
}
uint16_t l_port = reserve_port(sock->rsock->used_ports);
+ assert(l_port >= 32768);
DBG("using port %hu", l_port);
if (!l_port) {
fputs("we ran out of ports?\n", stderr);
@@ -390,6 +407,8 @@ static void cs_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
}
sock->l_port = htons(l_port);
+ sock->csum_p = csum_partial(&sock->l_port, sizeof(in_port_t), sock->rsock->csum_p);
+
HASH_ADD_KEYPTR(hh_ca, c_data->o_socks_by_caddr, sock->c_address, addresslen, sock);
HASH_ADD(hh_lp, sock->rsock->o_socks_by_lport, l_port, sizeof(in_port_t), sock);
@@ -398,10 +417,12 @@ static void cs_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
struct tcphdr buf = {
.th_sport = sock->l_port,
.th_dport = ((struct sockaddr_in *)sock->rsock->r_addr)->sin_port,
- .th_seq = htonl(sock->seq_num++),
+ .th_seq = htonl(sock->seq_num),
.th_flags = TH_SYN,
- .th_off = 5
+ .th_off = 5,
};
+ uint16_t tsz = htons(sizeof(buf));
+ buf.th_sum = ~csum_partial(&buf.th_seq, 16, csum_partial(&tsz, sizeof(tsz), sock->csum_p));
sock->pending_data = malloc(sz);
memcpy(sock->pending_data, rbuf, sz);
generated by cgit v1.2.3-70-g09d2 (git 2.47.0) at 2024-11-22 03:58:15 +0000