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-rw-r--r--Makefile4
-rw-r--r--siphash.c217
-rw-r--r--siphash.h5
-rw-r--r--tcp.c78
4 files changed, 295 insertions, 9 deletions
diff --git a/Makefile b/Makefile
index ca7a3e5..ebd5b20 100644
--- a/Makefile
+++ b/Makefile
@@ -2,8 +2,8 @@ CFLAGS += -Wall -Wextra -pedantic
all: passt qrap
-passt: passt.c passt.h arp.c arp.h dhcp.c dhcp.h ndp.c ndp.h tap.c tap.h tcp.c tcp.h udp.c udp.h util.c util.h
- $(CC) $(CFLAGS) passt.c arp.c dhcp.c ndp.c tap.c tcp.c udp.c util.c -o passt
+passt: passt.c passt.h arp.c arp.h dhcp.c dhcp.h ndp.c ndp.h siphash.c siphash.h tap.c tap.h tcp.c tcp.h udp.c udp.h util.c util.h
+ $(CC) $(CFLAGS) passt.c arp.c dhcp.c ndp.c siphash.c tap.c tcp.c udp.c util.c -o passt
qrap: qrap.c passt.h
$(CC) $(CFLAGS) qrap.c -o qrap
diff --git a/siphash.c b/siphash.c
new file mode 100644
index 0000000..910c718
--- /dev/null
+++ b/siphash.c
@@ -0,0 +1,217 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+/* PASST - Plug A Simple Socket Transport
+ *
+ * siphash.c - SipHash routines
+ *
+ * Copyright (c) 2020-2021 Red Hat GmbH
+ * Author: Stefano Brivio <sbrivio@redhat.com>
+ *
+ * This is an implementation of the SipHash-2-4-64 functions needed for TCP
+ * initial sequence numbers and socket lookup table hash for IPv4 and IPv6, see:
+ *
+ * Aumasson, J.P. and Bernstein, D.J., 2012, December. SipHash: a fast
+ * short-input PRF. In International Conference on Cryptology in India
+ * (pp. 489-508). Springer, Berlin, Heidelberg.
+ *
+ * http://cr.yp.to/siphash/siphash-20120918.pdf
+ *
+ * This includes code from the reference SipHash implementation at
+ * https://github.com/veorq/SipHash/ licensed as follows:
+ *
+ * --
+ * SipHash reference C implementation
+ *
+ * Copyright (c) 2012-2021 Jean-Philippe Aumasson
+ * <jeanphilippe.aumasson@gmail.com>
+ * Copyright (c) 2012-2014 Daniel J. Bernstein <djb@cr.yp.to>
+ *
+ * To the extent possible under law, the author(s) have dedicated all copyright
+ * and related and neighboring rights to this software to the public domain
+ * worldwide. This software is distributed without any warranty.
+ *
+ * You should have received a copy of the CC0 Public Domain Dedication along
+ * with
+ * this software. If not, see
+ * <http://creativecommons.org/publicdomain/zero/1.0/>.
+ * --
+ *
+ * and from the Linux kernel implementation (lib/siphash.c), licensed as
+ * follows:
+ *
+ * --
+ * Copyright (C) 2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
+ *
+ * This file is provided under a dual BSD/GPLv2 license.
+ * --
+ *
+ */
+
+#include <stdint.h>
+
+#include "siphash.h"
+
+#define ROTL(x, b) (uint64_t)(((x) << (b)) | ((x) >> (64 - (b))))
+
+#define PREAMBLE(len) \
+ uint64_t v[4] = { 0x736f6d6570736575ULL, 0x646f72616e646f6dULL, \
+ 0x6c7967656e657261ULL, 0x7465646279746573ULL }; \
+ uint64_t b = (uint64_t)(len) << 56; \
+ uint32_t ret; \
+ int __i; \
+ \
+ do { \
+ for (__i = sizeof(v) / sizeof(v[0]); __i >= 0; __i--) \
+ v[__i] = k[__i % 2]; \
+ } while (0)
+
+#define SIPROUND(n) \
+ do { \
+ for (__i = 0; __i < (n); __i++) { \
+ v[0] += v[1]; \
+ v[1] = ROTL(v[1], 13) ^ v[0]; \
+ v[0] = ROTL(v[0], 32); \
+ v[2] += v[3]; \
+ v[3] = ROTL(v[3], 16) ^ v[2]; \
+ v[0] += v[3]; \
+ v[3] = ROTL(v[3], 21) ^ v[0]; \
+ v[2] += v[1]; \
+ v[1] = ROTL(v[1], 17) ^ v[2]; \
+ v[2] = ROTL(v[2], 32); \
+ } \
+ } while (0)
+
+#define POSTAMBLE \
+ do { \
+ v[3] ^= b; \
+ SIPROUND(2); \
+ v[0] ^= b; \
+ v[2] ^= 0xff; \
+ SIPROUND(4); \
+ b = (v[0] ^ v[1]) ^ (v[2] ^ v[3]); \
+ ret = (uint32_t)(b >> 32) ^ (uint32_t)b; \
+ (void)ret; \
+ } while (0)
+
+/**
+ * siphash_8b() - Table index or timestamp offset for TCP over IPv4 (8 bytes in)
+ * @in: Input data (remote address and two ports, or two addresses)
+ * @k: Hash function key, 128 bits
+ *
+ * Return: the 64-bit hash output
+ */
+uint64_t siphash_8b(const uint8_t *in, const uint64_t *k)
+{
+ PREAMBLE(8);
+ v[3] ^= *(uint64_t *)in;
+ SIPROUND(2);
+ v[0] ^= *(uint64_t *)in;
+ POSTAMBLE;
+
+ return b;
+}
+
+/**
+ * siphash_12b() - Initial sequence number for TCP over IPv4 (12 bytes in)
+ * @in: Input data (two addresses, two ports)
+ * @k: Hash function key, 128 bits
+ *
+ * Return: 32 bits obtained by XORing the two halves of the 64-bit hash output
+ */
+uint32_t siphash_12b(const uint8_t *in, const uint64_t *k)
+{
+ uint32_t *in32 = (uint32_t *)in;
+ uint64_t combined;
+
+ combined = (uint64_t)(*(in32 + 1)) << 32 | *in32;
+
+ PREAMBLE(12);
+ v[3] ^= combined;
+ SIPROUND(2);
+ v[0] ^= combined;
+ b |= *(in32 + 2);
+ POSTAMBLE;
+
+ return ret;
+}
+
+/**
+ * siphash_20b() - Table index for TCP over IPv6 (20 bytes in)
+ * @in: Input data (remote address, two ports)
+ * @k: Hash function key, 128 bits
+ *
+ * Return: the 64-bit hash output
+ */
+uint64_t siphash_20b(const uint8_t *in, const uint64_t *k)
+{
+ uint32_t *in32 = (uint32_t *)in;
+ uint64_t combined;
+ int i;
+
+ PREAMBLE(20);
+
+ for (i = 0; i < 2; i++, in32 += 2) {
+ combined = (uint64_t)(*(in32 + 1)) << 32 | *in32;
+ v[3] ^= combined;
+ SIPROUND(2);
+ v[0] ^= combined;
+ }
+
+ b |= *in32;
+ POSTAMBLE;
+
+ return b;
+}
+
+/**
+ * siphash_32b() - Timestamp offset for TCP over IPv6 (32 bytes in)
+ * @in: Input data (two addresses)
+ * @k: Hash function key, 128 bits
+ *
+ * Return: the 64-bit hash output
+ */
+uint32_t siphash_32b(const uint8_t *in, const uint64_t *k)
+{
+ uint64_t *in64 = (uint64_t *)in;
+ int i;
+
+ PREAMBLE(32);
+
+ for (i = 0; i < 4; i++, in64++) {
+ v[3] ^= *in64;
+ SIPROUND(2);
+ v[0] ^= *in64;
+ }
+
+ POSTAMBLE;
+
+ return b;
+}
+
+/**
+ * siphash_36b() - Initial sequence number for TCP over IPv6 (36 bytes in)
+ * @in: Input data (two addresses, two ports)
+ * @k: Hash function key, 128 bits
+ *
+ * Return: 32 bits obtained by XORing the two halves of the 64-bit hash output
+ */
+uint32_t siphash_36b(const uint8_t *in, const uint64_t *k)
+{
+ uint32_t *in32 = (uint32_t *)in;
+ uint64_t combined;
+ int i;
+
+ PREAMBLE(36);
+
+ for (i = 0; i < 4; i++, in32 += 2) {
+ combined = (uint64_t)(*(in32 + 1)) << 32 | *in32;
+ v[3] ^= combined;
+ SIPROUND(2);
+ v[0] ^= combined;
+ }
+
+ b |= *in32;
+ POSTAMBLE;
+
+ return ret;
+}
diff --git a/siphash.h b/siphash.h
new file mode 100644
index 0000000..694fdc3
--- /dev/null
+++ b/siphash.h
@@ -0,0 +1,5 @@
+uint64_t siphash_8b(const uint8_t *in, const uint64_t *k);
+uint32_t siphash_12b(const uint8_t *in, const uint64_t *k);
+uint64_t siphash_20b(const uint8_t *in, const uint64_t *k);
+uint32_t siphash_32b(const uint8_t *in, const uint64_t *k);
+uint32_t siphash_36b(const uint8_t *in, const uint64_t *k);
diff --git a/tcp.c b/tcp.c
index f1de9cf..6c6a6dd 100644
--- a/tcp.c
+++ b/tcp.c
@@ -304,8 +304,9 @@
#include <stddef.h>
#include <string.h>
#include <sys/epoll.h>
-#include <sys/types.h>
+#include <sys/random.h>
#include <sys/socket.h>
+#include <sys/types.h>
#include <unistd.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
@@ -315,6 +316,7 @@
#include "passt.h"
#include "tap.h"
#include "util.h"
+#include "siphash.h"
/* Approximately maximum number of open descriptors per process */
#define MAX_CONNS (256 * 1024)
@@ -430,6 +432,7 @@ struct tcp_conn {
static char sock_buf[MAX_WINDOW];
static uint8_t tcp_act[MAX_CONNS / 8] = { 0 };
static struct tcp_conn tc[MAX_CONNS];
+static uint64_t hash_secret[2];
static int tcp_send_to_tap(struct ctx *c, int s, int flags, char *in, int len);
@@ -677,6 +680,60 @@ static void tcp_clamp_window(int s, struct tcphdr *th, int len, int init)
}
/**
+ * tcp_seq_init() - Calculate initial sequence number according to RFC 6528
+ * @c: Execution context
+ * @af: Address family, AF_INET or AF_INET6
+ * @addr: Remote address, pointer to sin_addr or sin6_addr
+ * @dstport: Destination port, connection-wise, network order
+ * @srcport: Source port, connection-wise, network order
+ *
+ * Return: initial TCP sequence
+ */
+static uint32_t tcp_seq_init(struct ctx *c, int af, void *addr,
+ in_port_t dstport, in_port_t srcport)
+{
+ struct timespec ts = { 0 };
+ uint32_t ns, seq;
+
+ clock_gettime(CLOCK_MONOTONIC, &ts);
+
+ if (af == AF_INET) {
+ struct {
+ struct in_addr src;
+ in_port_t srcport;
+ struct in_addr dst;
+ in_port_t dstport;
+ } __attribute__((__packed__)) in = {
+ .src = *(struct in_addr *)addr,
+ .srcport = srcport,
+ .dst = *(struct in_addr *)c->addr4,
+ .dstport = dstport,
+ };
+
+ seq = siphash_12b((uint8_t *)&in, hash_secret);
+ } else if (af == AF_INET6) {
+ struct {
+ struct in6_addr src;
+ in_port_t srcport;
+ struct in6_addr dst;
+ in_port_t dstport;
+ } __attribute__((__packed__)) in = {
+ .src = *(struct in6_addr *)addr,
+ .srcport = srcport,
+ .dst = c->addr6,
+ .dstport = dstport,
+ };
+
+ seq = siphash_36b((uint8_t *)&in, hash_secret);
+ }
+
+ ns = ts.tv_sec * 1E9;
+ ns += ts.tv_nsec >> 5; /* 32ns ticks, overflows 32 bits every 137s */
+
+ return seq + ns;
+}
+
+/**
* tcp_conn_from_tap() - Handle connection request (SYN segment) from tap
* @c: Execution context
* @af: Address family, AF_INET or AF_INET6
@@ -744,9 +801,8 @@ static void tcp_conn_from_tap(struct ctx *c, int af, void *addr,
tc[s].seq_from_tap = tc[s].seq_init_from_tap + 1;
tc[s].seq_ack_to_tap = tc[s].seq_from_tap;
- /* TODO: RFC 6528 with SipHash, worth it? */
- tc[s].seq_to_tap = 0;
- tc[s].seq_ack_from_tap = tc[s].seq_to_tap;
+ tc[s].seq_to_tap = tcp_seq_init(c, af, addr, th->dest, th->source);
+ tc[s].seq_ack_from_tap = tc[s].seq_to_tap + 1;
if (connect(s, sa, sl)) {
if (errno != EINPROGRESS) {
@@ -827,6 +883,10 @@ static void tcp_conn_from_sock(struct ctx *c, int fd)
tc[s].sock_port = sa4->sin_port;
tc[s].tap_port = ((struct sockaddr_in *)&sa_l)->sin_port;
+
+ tc[s].seq_to_tap = tcp_seq_init(c, AF_INET, &sa4->sin_addr,
+ tc[s].sock_port,
+ tc[s].tap_port);
} else if (sa_l.ss_family == AF_INET6) {
struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)&sa_r;
@@ -834,10 +894,12 @@ static void tcp_conn_from_sock(struct ctx *c, int fd)
tc[s].sock_port = sa6->sin6_port;
tc[s].tap_port = ((struct sockaddr_in6 *)&sa_l)->sin6_port;
+
+ tc[s].seq_to_tap = tcp_seq_init(c, AF_INET6, &sa6->sin6_addr,
+ tc[s].sock_port,
+ tc[s].tap_port);
}
- /* TODO: RFC 6528 with SipHash, worth it? */
- tc[s].seq_to_tap = 0;
tc[s].seq_ack_from_tap = tc[s].seq_to_tap + 1;
tc[s].tap_window = WINDOW_DEFAULT;
@@ -1230,7 +1292,7 @@ void tcp_sock_handler(struct ctx *c, int s, uint32_t events)
}
/**
- * tcp_sock_init() - Create and bind listening sockets for inbound connections
+ * tcp_sock_init() - Bind sockets for inbound connections, get key for sequence
* @c: Execution context
*
* Return: 0 on success, -1 on failure
@@ -1246,6 +1308,8 @@ int tcp_sock_init(struct ctx *c)
return -1;
}
+ getrandom(hash_secret, sizeof(hash_secret), GRND_RANDOM);
+
return 0;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-23 17:09:37 +0000