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-rw-r--r--Makefile6
-rw-r--r--src/checksum.c16
-rw-r--r--src/checksum.h12
-rw-r--r--src/client.c46
-rw-r--r--src/common.h2
-rw-r--r--src/server.c45
-rwxr-xr-xtest.sh27
7 files changed, 115 insertions, 39 deletions
diff --git a/Makefile b/Makefile
index bdc9167..796dec7 100644
--- a/Makefile
+++ b/Makefile
@@ -2,13 +2,13 @@ CFLAGS += -Wall -Wextra -Wwrite-strings -std=c99 -D_BSD_SOURCE -D_DEFAULT_SOURCE
LDLIBS := -lev
-NET_OBJS := src/client.o src/server.o
-OBJS := src/udpastcp.o src/checksum.o $(NET_OBJS)
+NET_OBJS := src/checksum.o src/client.o src/server.o
+OBJS := src/udpastcp.o $(NET_OBJS)
udpastcp: $(OBJS)
$(LINK.c) $^ $(LOADLIBES) $(LDLIBS) -o $@
-# networking code needs aliasing to be efficient
+# networking code needs aliasing to work at all
$(NET_OBJS): CFLAGS+=-fno-strict-aliasing -Wno-sign-compare
clean:
diff --git a/src/checksum.c b/src/checksum.c
index 5c6415a..53d4e5a 100644
--- a/src/checksum.c
+++ b/src/checksum.c
@@ -33,6 +33,7 @@
#include <assert.h>
#include <endian.h>
+#include <netinet/in.h>
#include <stdint.h>
#include "checksum.h"
@@ -127,3 +128,18 @@ uint16_t csum_partial(const void *buff, int len, uint16_t wsum)
result += 1;
return result;
}
+
+uint16_t csum_sockaddr_partial(const struct sockaddr *addr, int incl_port, uint16_t wsum)
+{
+ if (incl_port)
+ wsum = csum_partial(&((struct sockaddr_in *)addr)->sin_port, sizeof(in_port_t), wsum);
+
+ switch (addr->sa_family) {
+ case AF_INET:
+ return csum_partial(&((struct sockaddr_in *)addr)->sin_addr, sizeof(struct in_addr), wsum);
+ case AF_INET6:
+ return csum_partial(&((struct sockaddr_in6 *)addr)->sin6_addr, sizeof(struct in6_addr), wsum);
+ default:
+ abort();
+ }
+}
diff --git a/src/checksum.h b/src/checksum.h
index 7d4a003..700ee1a 100644
--- a/src/checksum.h
+++ b/src/checksum.h
@@ -1,5 +1,17 @@
+#include <netinet/in.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdlib.h>
+/* calculates the checksum of len bytes at buff when combined with wsum.
+ * return value is already in network order, but must be inverted before
+ * sending.
+ * example: hdr.th_sum = csum_partial(data, len, csum_partial(hdr, hdrlen, 0));
+ */
uint16_t csum_partial(const void *buff, int len, uint16_t wsum);
+
+/* calculates the checksum of a sockaddr_in or sockaddr_in6.
+ * if incl_port is set then the sin_port will be included.
+ * otherwise identical to csum_partial.
+ */
+uint16_t csum_sockaddr_partial(const struct sockaddr *addr, int incl_port, uint16_t wsum);
diff --git a/src/client.c b/src/client.c
index 380bf42..c78f3b1 100644
--- a/src/client.c
+++ b/src/client.c
@@ -5,6 +5,7 @@
#include <limits.h>
#include <netdb.h>
#include <netinet/in.h>
+#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <stdint.h>
#include <stdio.h>
@@ -20,8 +21,6 @@
#define PORTS_IN_INT (sizeof(int) * CHAR_BIT)
-#define IN_ADDR_PORT(addr) (((struct sockaddr_in *)addr)->sin_port)
-
struct c_data {
const char *r_host;
const char *r_port;
@@ -229,14 +228,31 @@ static void cc_cb(struct ev_loop *loop, ev_io *w, int revents __attribute__((unu
while ((rsz = recvfrom(w->fd, rbuf, sizeof(rbuf), 0, (struct sockaddr *)&rsock->c_data->pkt_addr, &pkt_addrlen)) != -1) {
DBG("received %zd raw bytes on client", rsz);
+ DBG("%u %zu", pkt_addrlen, sizeof(struct sockaddr_in6));
if (pkt_addrlen > sizeof(struct sockaddr_in6))
abort();
+ char *rptr = rbuf;
+
+ if (rsock->r_addr->sa_family == AF_INET) {
+ if ((size_t)rsz < sizeof(struct iphdr)) {
+ DBG("packet is smaller than IP header, ignoring");
+ return;
+ }
+
+ if (((struct iphdr *)rptr)->protocol != IPPROTO_TCP)
+ abort();
+
+ uint32_t ihl = ((struct iphdr *)rptr)->ihl * 4;
+ rptr = rptr + ihl;
+ rsz -= ihl;
+ }
+
if ((size_t)rsz < sizeof(struct tcphdr))
return;
- struct tcphdr *rhdr = (struct tcphdr *)rbuf;
+ struct tcphdr *rhdr = (struct tcphdr *)rptr;
struct o_c_sock *sock;
@@ -307,7 +323,7 @@ static void cc_cb(struct ev_loop *loop, ev_io *w, int revents __attribute__((unu
should_ssz = rsz - rhdr->th_off * 32 / CHAR_BIT;
if (should_ssz > 0) {
DBG("sending %zd bytes to client", should_ssz);
- ssz = sendto(rsock->c_data->s_sock, rbuf + rhdr->th_off * 32 / CHAR_BIT, should_ssz, 0, sock->c_address, rsock->c_data->s_addrlen);
+ ssz = sendto(rsock->c_data->s_sock, rptr + rhdr->th_off * 32 / CHAR_BIT, should_ssz, 0, sock->c_address, rsock->c_data->s_addrlen);
if (ssz < 0) {
perror("sendto");
@@ -367,25 +383,9 @@ static inline struct o_c_rsock * c_rsock_init(struct addrinfo *res) {
if (rsock->r_addr->sa_family != our_addr.ss_family)
abort();
- size_t addr_offset, addr_size;
-
- switch (our_addr.ss_family) {
- case AF_INET:
- addr_offset = offsetof(struct sockaddr_in, sin_addr);
- addr_size = sizeof(in_addr_t);
- break;
- case AF_INET6:
- addr_offset = offsetof(struct sockaddr_in6, sin6_addr);
- addr_size = sizeof(struct in6_addr);
- break;
- default:
- abort();
- }
-
- rsock->csum_p = csum_partial(&IN_ADDR_PORT(rsock->r_addr), sizeof(in_port_t),
- csum_partial(proto, sizeof(proto),
- csum_partial((char *)&our_addr + addr_offset, addr_size,
- csum_partial((char *)rsock->r_addr + addr_offset, addr_size, 0))));
+ rsock->csum_p = csum_partial(proto, sizeof(proto),
+ csum_sockaddr_partial((struct sockaddr *)&our_addr, 0,
+ csum_sockaddr_partial(rsock->r_addr, 1, 0)));
return rsock;
}
diff --git a/src/common.h b/src/common.h
index f78b2ba..5800581 100644
--- a/src/common.h
+++ b/src/common.h
@@ -3,3 +3,5 @@
#else
#define DBG(...)
#endif
+
+#define IN_ADDR_PORT(addr) (((struct sockaddr_in *)addr)->sin_port)
diff --git a/src/server.c b/src/server.c
index 462212f..098c313 100644
--- a/src/server.c
+++ b/src/server.c
@@ -4,6 +4,7 @@
#include <fcntl.h>
#include <netdb.h>
#include <netinet/in.h>
+#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <stdint.h>
#include <stdio.h>
@@ -11,7 +12,9 @@
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>
+
#include "common.h"
+#include "checksum.h"
#include "server.h"
#include "uthash.h"
@@ -23,6 +26,7 @@ struct o_s_sock {
UT_hash_handle hh;
int c_sock;
uint16_t seq_num;
+ uint16_t csum_p;
uint8_t status;
};
@@ -34,6 +38,7 @@ struct s_data {
struct o_s_sock *o_socks_by_caddr;
int s_sock;
socklen_t s_addrlen;
+ uint16_t csum_p;
};
static inline void s_prep_c_addr(struct o_s_sock *sock, struct tcphdr *hdr) {
@@ -153,6 +158,22 @@ static void ss_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
if (c_addrlen != s_data->s_addrlen)
abort();
+ char *rptr = rbuf;
+
+ if (s_data->s_addr->sa_family == AF_INET) {
+ if ((size_t)sz < sizeof(struct iphdr)) {
+ DBG("packet is smaller than IP header, ignoring");
+ return;
+ }
+
+ if (((struct iphdr *)rbuf)->protocol != IPPROTO_TCP)
+ abort();
+
+ uint32_t ihl = ((struct iphdr *)rbuf)->ihl * 4;
+ rptr = rbuf + ihl;
+ sz -= ihl;
+ }
+
#ifdef DEBUG
char hbuf[NI_MAXHOST];
r = getnameinfo((struct sockaddr *)&s_data->pkt_addr, c_addrlen, hbuf, sizeof(hbuf), NULL, 0, NI_NUMERICHOST);
@@ -161,7 +182,7 @@ static void ss_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
ev_break(EV_A_ EVBREAK_ONE);
return;
}
- DBG("received %zd bytes from %s", sz, hbuf);
+ DBG("received %zd payload bytes from %s", sz, hbuf);
#endif
if ((size_t)sz < sizeof(struct tcphdr)) {
@@ -169,7 +190,7 @@ static void ss_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
return;
}
- struct tcphdr *tcphdr = (struct tcphdr *)rbuf;
+ struct tcphdr *tcphdr = (struct tcphdr *)rptr;
DBG("packet received on port %hu", ntohs(tcphdr->th_dport));
@@ -201,6 +222,8 @@ static void ss_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
sock->c_sock = -1;
sock->status = TCP_SYN_RECV;
+ sock->csum_p = csum_sockaddr_partial((struct sockaddr *)&s_data->pkt_addr, 1, s_data->csum_p);
+
struct tcphdr buf = {
.th_sport = tcphdr->th_dport,
.th_dport = tcphdr->th_sport,
@@ -210,6 +233,9 @@ static void ss_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
.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));
+
HASH_ADD(hh, s_data->o_socks_by_caddr, c_addr, c_addrlen, sock);
((struct sockaddr_in *)&s_data->pkt_addr)->sin_port = htons(0);
@@ -239,11 +265,13 @@ static void ss_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
return;
}
+ /*
if (th_flags == TH_RST) {
DBG("RST received, cleaning up socket");
sock->status = TCP_CLOSE;
s_sock_cleanup(EV_A_ sock);
}
+ */
if (th_flags & ~(TH_PUSH | TH_ACK)) {
DBG("TCP flags not PSH and/or ACK, dropping packet");
@@ -297,7 +325,7 @@ static void ss_cb(EV_P_ ev_io *w, int revents __attribute__((unused))) {
assert(sock->status == TCP_ESTABLISHED);
DBG("sending %zu bytes to client", (size_t)(sz - tcphdr->th_off * 4));
- sz = send(sock->c_sock, rbuf + tcphdr->th_off * 4, sz - tcphdr->th_off * 4, 0);
+ sz = send(sock->c_sock, rptr + tcphdr->th_off * 4, sz - tcphdr->th_off * 4, 0);
if (sz < 0) {
perror("send");
ev_break(EV_A_ EVBREAK_ONE);
@@ -323,11 +351,15 @@ int start_server(const char *s_host, const char *s_port, const char *r_host, con
return 1;
}
+ char proto[] = { 0, IPPROTO_TCP };
+
struct s_data s_data = {
.s_addr = res->ai_addr,
.s_addrlen = res->ai_addrlen,
.r_host = r_host,
- .r_port = r_port
+ .r_port = r_port,
+ .csum_p = csum_sockaddr_partial(res->ai_addr, 1,
+ csum_partial(&proto, sizeof(proto), 0))
};
s_data.s_sock = socket(s_data.s_addr->sa_family, SOCK_RAW, IPPROTO_TCP);
@@ -337,6 +369,11 @@ int start_server(const char *s_host, const char *s_port, const char *r_host, con
return 1;
}
+ if (bind(s_data.s_sock, res->ai_addr, res->ai_addrlen) == -1) {
+ perror("bind");
+ return 2;
+ }
+
if (fcntl(s_data.s_sock, F_SETFL, O_NONBLOCK) == -1) {
perror("fcntl");
freeaddrinfo(res);
diff --git a/test.sh b/test.sh
index c0668fb..842d530 100755
--- a/test.sh
+++ b/test.sh
@@ -1,17 +1,17 @@
#!/bin/sh
# this script tests basic udpastcp functionality.
-test1() {
+test_bidi() {
(
pids=
trap 'kill $pids' EXIT
- ./udpastcp client localhost 36563 localhost 64109 &
+ ./udpastcp client "$1" 36563 "$1" 64109 &
pids="$!"
- ./udpastcp server localhost 64109 localhost 41465 &
+ ./udpastcp server "$1" 64109 "$1" 41465 &
pids="$pids $!"
- ( ( sleep 0.4; echo BBBBBBBB; ) | socat udp6-listen:41465 - ) &
+ ( ( sleep 0.4; echo BBBBBBBB; ) | socat "udp-listen:41465,pf=${2}" - ) &
pids="$pids $!"
- ( ( sleep 0.2; echo AAAAAAAA; ) | socat - 'udp-connect:[::1]:36563' ) &
+ ( ( sleep 0.2; echo AAAAAAAA; ) | socat - "udp-connect:localhost:36563,pf=${2}" ) &
pids="$pids $!"
sleep 0.5
)
@@ -20,9 +20,18 @@ test1() {
nl='
'
-if [ "$( test1 )" = "AAAAAAAA${nl}BBBBBBBB" ]; then
- echo "Test succeeded."
+if [ "$( test_bidi 127.0.0.1 ip4 )" = "AAAAAAAA${nl}BBBBBBBB" ]; then
+ echo "IPv4 test succeeded."
else
- echo "Test failed."
- exit 1
+ echo "IPv4 test failed."
+ r=1
fi
+
+if [ "$( test_bidi ::1 ip6 )" = "AAAAAAAA${nl}BBBBBBBB" ]; then
+ echo "IPv6 test succeeded."
+else
+ echo "IPv6 test failed."
+ r=1
+fi
+
+exit $r
generated by cgit v1.2.3-70-g09d2 (git 2.47.0) at 2024-11-23 09:35:03 +0000