1/*
2 * util/proxy_protocol.c - event notification
3 *
4 * Copyright (c) 2022, NLnet Labs. All rights reserved.
5 *
6 * This software is open source.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * Redistributions of source code must retain the above copyright notice,
13 * this list of conditions and the following disclaimer.
14 *
15 * Redistributions in binary form must reproduce the above copyright notice,
16 * this list of conditions and the following disclaimer in the documentation
17 * and/or other materials provided with the distribution.
18 *
19 * Neither the name of the NLNET LABS nor the names of its contributors may
20 * be used to endorse or promote products derived from this software without
21 * specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35
36/**
37 * \file
38 *
39 * This file contains PROXY protocol functions.
40 */
41#include "util/proxy_protocol.h"
42
43/**
44 * Internal struct initialized with function pointers for writing uint16 and
45 * uint32.
46 */
47struct proxy_protocol_data {
48	void (*write_uint16)(void* buf, uint16_t data);
49	void (*write_uint32)(void* buf, uint32_t data);
50};
51struct proxy_protocol_data pp_data;
52
53/**
54 * Internal lookup table; could be further generic like sldns_lookup_table
55 * for all the future generic stuff.
56 */
57struct proxy_protocol_lookup_table {
58	int id;
59	const char *text;
60};
61
62/**
63 * Internal parsing error text; could be exposed with pp_lookup_error.
64 */
65static struct proxy_protocol_lookup_table pp_parse_errors_data[] = {
66	{ PP_PARSE_NOERROR, "no parse error" },
67	{ PP_PARSE_SIZE, "not enough space for header" },
68	{ PP_PARSE_WRONG_HEADERv2, "could not match PROXYv2 header" },
69	{ PP_PARSE_UNKNOWN_CMD, "unknown command" },
70	{ PP_PARSE_UNKNOWN_FAM_PROT, "unknown family and protocol" },
71};
72
73void
74pp_init(void (*write_uint16)(void* buf, uint16_t data),
75	void (*write_uint32)(void* buf, uint32_t data)) {
76	pp_data.write_uint16 = write_uint16;
77	pp_data.write_uint32 = write_uint32;
78}
79
80const char*
81pp_lookup_error(enum pp_parse_errors error) {
82	return pp_parse_errors_data[error].text;
83}
84
85size_t
86pp2_write_to_buf(uint8_t* buf, size_t buflen,
87#ifdef INET6
88	struct sockaddr_storage* src,
89#else
90	struct sockaddr_in* src,
91#endif
92	int stream)
93{
94	int af;
95	size_t expected_size;
96	if(!src) return 0;
97	af = (int)((struct sockaddr_in*)src)->sin_family;
98	expected_size = PP2_HEADER_SIZE + (af==AF_INET?12:36);
99	if(buflen < expected_size) {
100		return 0;
101	}
102	/* sig */
103	memcpy(buf, PP2_SIG, PP2_SIG_LEN);
104	buf += PP2_SIG_LEN;
105	/* version and command */
106	*buf = (PP2_VERSION << 4) | PP2_CMD_PROXY;
107	buf++;
108	switch(af) {
109	case AF_INET:
110		/* family and protocol */
111		*buf = (PP2_AF_INET<<4) |
112			(stream?PP2_PROT_STREAM:PP2_PROT_DGRAM);
113		buf++;
114		/* length */
115		(*pp_data.write_uint16)(buf, 12);
116		buf += 2;
117		/* src addr */
118		memcpy(buf,
119			&((struct sockaddr_in*)src)->sin_addr.s_addr, 4);
120		buf += 4;
121		/* dst addr */
122		(*pp_data.write_uint32)(buf, 0);
123		buf += 4;
124		/* src port */
125		memcpy(buf,
126			&((struct sockaddr_in*)src)->sin_port, 2);
127		buf += 2;
128		/* dst addr */
129		/* dst port */
130		(*pp_data.write_uint16)(buf, 12);
131		break;
132#ifdef INET6
133	case AF_INET6:
134		/* family and protocol */
135		*buf = (PP2_AF_INET6<<4) |
136			(stream?PP2_PROT_STREAM:PP2_PROT_DGRAM);
137		buf++;
138		/* length */
139		(*pp_data.write_uint16)(buf, 36);
140		buf += 2;
141		/* src addr */
142		memcpy(buf,
143			&((struct sockaddr_in6*)src)->sin6_addr, 16);
144		buf += 16;
145		/* dst addr */
146		memset(buf, 0, 16);
147		buf += 16;
148		/* src port */
149		memcpy(buf, &((struct sockaddr_in6*)src)->sin6_port, 2);
150		buf += 2;
151		/* dst port */
152		(*pp_data.write_uint16)(buf, 0);
153		break;
154#endif /* INET6 */
155	case AF_UNIX:
156		/* fallthrough */
157	default:
158		return 0;
159	}
160	return expected_size;
161}
162
163int
164pp2_read_header(uint8_t* buf, size_t buflen)
165{
166	size_t size;
167	struct pp2_header* header = (struct pp2_header*)buf;
168	/* Try to fail all the unsupported cases first. */
169	if(buflen < PP2_HEADER_SIZE) {
170		return PP_PARSE_SIZE;
171	}
172	/* Check for PROXYv2 header */
173	if(memcmp(header, PP2_SIG, PP2_SIG_LEN) != 0 ||
174		((header->ver_cmd & 0xF0)>>4) != PP2_VERSION) {
175		return PP_PARSE_WRONG_HEADERv2;
176	}
177	/* Check the length */
178	size = PP2_HEADER_SIZE + ntohs(header->len);
179	if(buflen < size) {
180		return PP_PARSE_SIZE;
181	}
182	/* Check for supported commands */
183	if((header->ver_cmd & 0xF) != PP2_CMD_LOCAL &&
184		(header->ver_cmd & 0xF) != PP2_CMD_PROXY) {
185		return PP_PARSE_UNKNOWN_CMD;
186	}
187	/* Check for supported family and protocol */
188	if(header->fam_prot != PP2_UNSPEC_UNSPEC &&
189		header->fam_prot != PP2_INET_STREAM &&
190		header->fam_prot != PP2_INET_DGRAM &&
191		header->fam_prot != PP2_INET6_STREAM &&
192		header->fam_prot != PP2_INET6_DGRAM &&
193		header->fam_prot != PP2_UNIX_STREAM &&
194		header->fam_prot != PP2_UNIX_DGRAM) {
195		return PP_PARSE_UNKNOWN_FAM_PROT;
196	}
197	/* We have a correct header */
198	return PP_PARSE_NOERROR;
199}
200