diff options
Diffstat (limited to 'proxy-proto.c')
| -rw-r--r-- | proxy-proto.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/proxy-proto.c b/proxy-proto.c new file mode 100644 index 0000000..e90c851 --- /dev/null +++ b/proxy-proto.c @@ -0,0 +1,213 @@ +/* + * Copyright (c) 2024 github.com/Sir-Photch <sir-photch@posteo.me> + * + * Permission to use, copy, modify, and distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + */ + +#include "gmid.h" + +#include <stdint.h> +#include <string.h> + +#define MIN(a, b) (a) < (b) ? (a) : (b) + +static int +check_prefix_v1(char **buf) +{ + static const char PROXY[6] = "PROXY "; + + if (0 != strncmp(*buf, PROXY, sizeof(PROXY))) + return PROXY_PROTO_PARSE_FAIL; + + *buf += sizeof(PROXY); + + return PROXY_PROTO_PARSE_SUCCESS; +} + +static int +check_proto_v1(char **buf) +{ + static const char TCP[3] = "TCP"; + + if (0 != strncmp(*buf, TCP, sizeof(TCP))) + return PROXY_PROTO_PARSE_FAIL; + + *buf += sizeof(TCP); + + int type; + switch ((*buf)[0]) { + case '4': type = 4; break; + case '6': type = 6; break; + default: return PROXY_PROTO_PARSE_FAIL; + } + + // '4' / '6' + ' ' + *buf += 2; + + return type; +} + +static int +check_unknown_v1(char **buf) +{ + static const char UNKNOWN[7] = "UNKNOWN"; + + if (0 != strncmp(*buf, UNKNOWN, sizeof(UNKNOWN))) + return PROXY_PROTO_PARSE_FAIL; + + *buf += sizeof(UNKNOWN); + + return PROXY_PROTO_PARSE_SUCCESS; +} + +static int +check_crlf_v1(char *const *buf, size_t buflen) +{ + static const char CRLF[2] = "\r\n"; + + if (buflen < sizeof(CRLF)) + return PROXY_PROTO_PARSE_FAIL; + + if (!memmem(*buf, buflen, CRLF, sizeof(CRLF))) + return PROXY_PROTO_PARSE_FAIL; + + return PROXY_PROTO_PARSE_SUCCESS; +} + +static int +check_ip_v1(int af, void *addr, char **buf) +{ + char *spc; + + if (NULL == (spc = strchr(*buf, ' '))) + return PROXY_PROTO_PARSE_FAIL; + + *spc++ = '\0'; + + if (1 != inet_pton(af, *buf, addr)) + return PROXY_PROTO_PARSE_FAIL; + + *buf = spc; + + return PROXY_PROTO_PARSE_SUCCESS; +} + +static int +check_port_v1(uint16_t *port, char **buf, size_t *buflen) +{ + size_t wspc_idx = strcspn(*buf, " \r"); + char *wspc = *buf + wspc_idx; + + if (!(' ' == *wspc || '\r' == *wspc)) + return PROXY_PROTO_PARSE_FAIL; + + *wspc++ = '\0'; + + const char *errstr; + long long num = strtonum(*buf, 0, UINT16_MAX, &errstr); + if (errstr) + return PROXY_PROTO_PARSE_FAIL; + + *buf = wspc; + *port = num; + + return PROXY_PROTO_PARSE_SUCCESS; +} + +#define EXPECT_SUCCESS(call) do { \ + ret = (call); \ + if (PROXY_PROTO_PARSE_SUCCESS != ret) \ + return ret; \ +} while (0) + +int proxy_proto_v1_parse(struct proxy_protocol_v1 *s, char *buf, size_t buflen, size_t *consumed) +{ + const char *begin = buf; + int ret; + + EXPECT_SUCCESS(check_crlf_v1(&buf, buflen)); + EXPECT_SUCCESS(check_prefix_v1(&buf)); + + ret = check_proto_v1(&buf); + switch (ret) + { + case 4: s->proto = PROTO_V4; break; + case 6: s->proto = PROTO_V6; break; + case PROXY_PROTO_PARSE_FAIL: { + EXPECT_SUCCESS(check_unknown_v1(&buf)); + + s->proto = PROTO_UNKNOWN; + return PROXY_PROTO_PARSE_SUCCESS; + } break; + default: return ret; + } + + switch (s->proto) + { + case PROTO_V4: { + EXPECT_SUCCESS(check_ip_v1(AF_INET, &s->srcaddr.v4, &buf)); + EXPECT_SUCCESS(check_ip_v1(AF_INET, &s->dstaddr.v4, &buf)); + } break; + + case PROTO_V6: { + EXPECT_SUCCESS(check_ip_v1(AF_INET6, &s->srcaddr.v6, &buf)); + EXPECT_SUCCESS(check_ip_v1(AF_INET6, &s->dstaddr.v6, &buf)); + } break; + + default: ASSERT_MSG(0, "unimplemented"); + } + + EXPECT_SUCCESS(check_port_v1(&s->srcport, &buf, &buflen)); + EXPECT_SUCCESS(check_port_v1(&s->dstport, &buf, &buflen)); + + assert('\n' == *buf); + buf += 1; + + *consumed = buf - begin; + return PROXY_PROTO_PARSE_SUCCESS; +} + +int +proxy_proto_v1_string(const struct proxy_protocol_v1 *s, char* buf, size_t buflen) +{ + // "0000:0000:0000:0000:0000:0000:0000:0000\0" + char srcaddrbuf[40], dstaddrbuf[40]; + int ret; + switch (s->proto) + { + case PROTO_UNKNOWN: ret = snprintf(buf, buflen, "unknown"); goto fin; + case PROTO_V4: { + inet_ntop(AF_INET, &s->srcaddr.v4, srcaddrbuf, 39); + inet_ntop(AF_INET, &s->dstaddr.v4, dstaddrbuf, 39); + } break; + case PROTO_V6: { + inet_ntop(AF_INET6, &s->srcaddr.v6, srcaddrbuf, 39); + inet_ntop(AF_INET6, &s->dstaddr.v6, dstaddrbuf, 39); + } break; + } + + srcaddrbuf[39] = dstaddrbuf[39] = '\0'; + + ret = snprintf( + buf, + buflen, + "from %s port %u via %s port %u", + srcaddrbuf, + s->srcport, + dstaddrbuf, + s->dstport + ); + +fin: + return ret; +} |