Adding upstream version 3.3.4.upstream/3.3.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 281 insertions, 0 deletions

diff --git a/src/contrib/proxyv2/proxyv2.c b/src/contrib/proxyv2/proxyv2.c
new file mode 100644
index 0000000..0e5c90b
--- /dev/null
+++ b/src/contrib/proxyv2/proxyv2.c
@@ -0,0 +1,281 @@
+/*  Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+    Copyright (C) 2021 Fastly, Inc.
+
+    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 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <arpa/inet.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "contrib/proxyv2/proxyv2.h"
+#include "contrib/sockaddr.h"
+#include "libknot/errcode.h"
+
+/*
+ * Minimal implementation of the haproxy PROXY v2 protocol.
+ *
+ * Supports extracting the original client address and client port number from
+ * the haproxy PROXY v2 protocol's address block.
+ *
+ * See https://www.haproxy.org/download/2.5/doc/proxy-protocol.txt for the
+ * protocol specification.
+ */
+
+static const char PROXYV2_SIG[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
+
+/*
+ * The part of the PROXY v2 payload following the signature.
+ */
+struct proxyv2_hdr {
+	/*
+	 * The protocol version and command.
+	 *
+	 * The upper four bits contain the version which must be \x2 and the
+	 * receiver must only accept this value.
+	 *
+	 * The lower four bits represent the command, which is \x0 for LOCAL
+	 * and \x1 for PROXY.
+	 */
+	uint8_t		ver_cmd;
+
+	/*
+	 * The transport protocol and address family. The upper four bits
+	 * contain the address family and the lower four bits contain the
+	 * protocol.
+	 *
+	 * The relevant values for DNS are:
+	 *	\x11: TCP over IPv4
+	 *	\x12: UDP over IPv4
+	 *	\x21: TCP over IPv6
+	 *	\x22: UDP over IPv6
+	 */
+	uint8_t		fam_addr;
+
+	/*
+	 * The number of PROXY v2 payload bytes following this header to skip
+	 * to reach the proxied packet (i.e., start of the original DNS message).
+	 */
+	uint16_t	len;
+};
+
+/*
+ * The PROXY v2 address block for IPv4.
+ */
+struct proxyv2_addr_ipv4 {
+	uint8_t		src_addr[4];
+	uint8_t		dst_addr[4];
+	uint16_t	src_port;
+	uint16_t	dst_port;
+};
+
+/*
+ * The PROXY v2 address block for IPv6.
+ */
+struct proxyv2_addr_ipv6 {
+	uint8_t		src_addr[16];
+	uint8_t		dst_addr[16];
+	uint16_t	src_port;
+	uint16_t	dst_port;
+};
+
+const size_t PROXYV2_HEADER_MAXLEN = sizeof(PROXYV2_SIG) +
+                                     sizeof(struct proxyv2_hdr) +
+                                     sizeof(struct proxyv2_addr_ipv6);
+
+/*
+ * Make sure the C compiler lays out the PROXY v2 address block structs so that
+ * they can be memcpy()'d off the wire.
+ */
+#if (__STDC_VERSION__ >= 201112L)
+_Static_assert(sizeof(struct proxyv2_hdr) == 4,
+	       "struct proxyv2_hdr is correct size");
+_Static_assert(sizeof(struct proxyv2_addr_ipv4) == 12,
+	       "struct proxyv2_addr_ipv4 is correct size");
+_Static_assert(sizeof(struct proxyv2_addr_ipv6) == 36,
+	       "struct proxyv2_addr_ipv6 is correct size");
+#endif
+
+int proxyv2_header_offset(void *base, size_t len_base)
+{
+	/*
+	 * Check that 'base' has enough bytes to read the PROXY v2 signature
+	 * and header, and if so whether the PROXY v2 signature is present.
+	 */
+	if (len_base < (sizeof(PROXYV2_SIG) + sizeof(struct proxyv2_hdr)) ||
+	    memcmp(base, PROXYV2_SIG, sizeof(PROXYV2_SIG)) != 0)
+	{
+		/* Failure. */
+		return KNOT_EMALF;
+	}
+
+	/* Read the PROXY v2 header. */
+	struct proxyv2_hdr *hdr = base + sizeof(PROXYV2_SIG);
+
+	/*
+	 * Check that this is a version 2, command "PROXY" payload.
+	 *
+	 * XXX: The PROXY v2 spec mandates support for the "LOCAL" command
+	 * (byte 0x20).
+	 */
+	if (hdr->ver_cmd != 0x21) {
+		/* Failure. */
+		return KNOT_EMALF;
+	}
+
+	/*
+	 * Calculate the offset of the original DNS message inside the packet.
+	 * This needs to account for the length of the PROXY v2 signature,
+	 * PROXY v2 header, and the bytes of variable length PROXY v2 data
+	 * following the PROXY v2 header.
+	 */
+	const size_t offset_dns = sizeof(PROXYV2_SIG) +
+	                          sizeof(struct proxyv2_hdr) + ntohs(hdr->len);
+	if (offset_dns < len_base) {
+		return offset_dns;
+	}
+
+	return KNOT_EMALF;
+}
+
+int proxyv2_addr_store(void *base, size_t len_base, struct sockaddr_storage *ss)
+{
+	/*
+	 * Calculate the offset of the PROXY v2 address block. This is the data
+	 * immediately following the PROXY v2 header.
+	 */
+	const size_t offset_proxy_addr = sizeof(PROXYV2_SIG) +
+	                                 sizeof(struct proxyv2_hdr);
+	struct proxyv2_hdr *hdr = base + sizeof(PROXYV2_SIG);
+
+	/*
+	 * Handle proxied UDP-over-IPv4 and UDP-over-IPv6 packets.
+	 */
+	//TODO What about TCP?
+	if (hdr->fam_addr == 0x12) {
+		/* This is a proxied UDP-over-IPv4 packet. */
+		struct proxyv2_addr_ipv4 *addr;
+
+		/*
+		 * Check that the packet is large enough to contain the IPv4
+		 * address block.
+		 */
+		if (offset_proxy_addr + sizeof(*addr) < len_base) {
+			/* Read the PROXY v2 address block. */
+			addr = base + offset_proxy_addr;
+
+			/* Copy the client's IPv4 address to the caller. */
+			sockaddr_set_raw(ss, AF_INET, addr->src_addr,
+					 sizeof(addr->src_addr));
+
+			/* Copy the client's port to the caller. */
+			sockaddr_port_set(ss, ntohs(addr->src_port));
+
+			/* Success. */
+			return KNOT_EOK;
+		}
+	} else if (hdr->fam_addr == 0x22) {
+		/* This is a proxied UDP-over-IPv6 packet. */
+		struct proxyv2_addr_ipv6 *addr;
+
+		/*
+		 * Check that the packet is large enough to contain the IPv6
+		 * address block.
+		 */
+		if (offset_proxy_addr + sizeof(*addr) < len_base) {
+			/* Read the PROXY v2 address block. */
+			addr = base + offset_proxy_addr;
+
+			/* Copy the client's IPv6 address to the caller. */
+			sockaddr_set_raw(ss, AF_INET6, addr->src_addr,
+					 sizeof(addr->src_addr));
+
+			/* Copy the client's port to the caller. */
+			sockaddr_port_set(ss, ntohs(addr->src_port));
+
+			/* Success. */
+			return KNOT_EOK;
+		}
+	}
+
+	/* Failure. */
+	return KNOT_EMALF;
+}
+
+int proxyv2_write_header(char *buf, size_t buflen, int socktype, const struct sockaddr *src,
+                         const struct sockaddr *dst)
+{
+	if (buflen < PROXYV2_HEADER_MAXLEN) {
+		return KNOT_EINVAL;
+	}
+
+	uint8_t fam_addr = 0;
+	int family = src->sa_family;
+	if (socktype == SOCK_DGRAM) {
+		fam_addr += 0x2;
+	} else if (socktype == SOCK_STREAM) {
+		fam_addr += 0x1;
+	} else {
+		return KNOT_EINVAL;
+	}
+	if (family == AF_INET) {
+		fam_addr += 0x10;
+	} else if (family == AF_INET6) {
+		fam_addr += 0x20;
+	} else {
+		return KNOT_EINVAL;
+	}
+
+	struct proxyv2_hdr hdr = {
+		.ver_cmd = 0x21,
+		.fam_addr = fam_addr,
+		.len = (family == AF_INET)
+		       ? htons(sizeof(struct proxyv2_addr_ipv4))
+		       : htons(sizeof(struct proxyv2_addr_ipv6))
+	};
+
+	size_t offset = 0;
+	memcpy(buf, PROXYV2_SIG, sizeof(PROXYV2_SIG));
+	offset += sizeof(PROXYV2_SIG);
+	memcpy(buf + offset, &hdr, sizeof(hdr));
+	offset += sizeof(hdr);
+
+	if (family == AF_INET) {
+		struct proxyv2_addr_ipv4 ipv4 = { 0 };
+		struct sockaddr_in *p_src = (struct sockaddr_in *)src;
+		struct sockaddr_in *p_dst = (struct sockaddr_in *)dst;
+		memcpy(ipv4.src_addr, &p_src->sin_addr, sizeof(p_src->sin_addr));
+		memcpy(ipv4.dst_addr, &p_dst->sin_addr, sizeof(p_dst->sin_addr));
+		ipv4.src_port = p_src->sin_port;
+		ipv4.dst_port = p_dst->sin_port;
+
+		// Store in buffer
+		memcpy(buf + offset, &ipv4, sizeof(ipv4));
+		offset += sizeof(ipv4);
+	} else {
+		struct proxyv2_addr_ipv6 ipv6 = { 0 };
+		struct sockaddr_in6 *p_src = (struct sockaddr_in6 *)src;
+		struct sockaddr_in6 *p_dst = (struct sockaddr_in6 *)dst;
+		memcpy(ipv6.src_addr, &p_src->sin6_addr, sizeof(p_src->sin6_addr));
+		memcpy(ipv6.dst_addr, &p_dst->sin6_addr, sizeof(p_dst->sin6_addr));
+		ipv6.src_port = p_src->sin6_port;
+		ipv6.dst_port = p_dst->sin6_port;
+
+		// Store in buffer
+		memcpy(buf + offset, &ipv6, sizeof(ipv6));
+		offset += sizeof(ipv6);
+	}
+
+	return offset;
+}