mirror of
https://github.com/Waujito/youtubeUnblock.git
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Add crypto files
This commit is contained in:
Vadim Vetrov
346
src/quic.c
Normal file
346
src/quic.c
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@@ -0,0 +1,346 @@
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#include "quic.h"
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#include "logging.h"
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/**
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* Packet number.
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*/
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struct quic_pnumber {
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uint8_t d1;
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uint8_t d2;
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uint8_t d3;
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uint8_t d4;
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};
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uint64_t quic_parse_varlength(const uint8_t *variable, uint64_t *mlen) {
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if (mlen && *mlen == 0) return 0;
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uint64_t vr = (*variable & 0x3F);
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uint8_t len = 1 << (*variable >> 6);
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if (mlen) {
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if (*mlen < len) return 0;
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*mlen = len;
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}
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++variable;
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for (uint8_t i = 1; i < len; i++) {
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vr = (vr << 8) + *variable;
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++variable;
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}
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return vr;
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}
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int64_t quic_get_version(const struct quic_lhdr *qch) {
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int64_t qversion = ntohl(qch->version);
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switch (qversion) {
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case QUIC_V1:
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case QUIC_V2:
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return qversion;
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default:
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return -qversion;
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}
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}
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int quic_check_is_initial(const struct quic_lhdr *qch) {
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int64_t qversion = quic_get_version(qch);
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if (qversion < 0) return 0;
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uint8_t qtype = qch->type;
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switch (qversion) {
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case QUIC_V1:
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qtype = quic_convtype_v1(qtype);
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break;
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case QUIC_V2:
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qtype = quic_convtype_v2(qtype);
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break;
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default:
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return 0;
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}
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if (qtype != QUIC_INITIAL_TYPE) {
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return 0;
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}
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return 1;
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}
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int quic_parse_data(const uint8_t *raw_payload, uint32_t raw_payload_len,
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const struct quic_lhdr **qch, uint32_t *qch_len,
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struct quic_cids *qci,
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const uint8_t **payload, uint32_t *plen) {
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if ( raw_payload == NULL ||
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raw_payload_len < sizeof(struct quic_lhdr))
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goto invalid_packet;
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const struct quic_lhdr *nqch = (const struct quic_lhdr *)raw_payload;
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uint32_t left_len = raw_payload_len - sizeof(struct quic_lhdr);
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const uint8_t *cur_rawptr = raw_payload + sizeof(struct quic_lhdr);
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if (!nqch->fixed) {
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lgtrace_addp("quic fixed unset");
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return -EPROTO;
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}
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int64_t qversion = quic_get_version(nqch);
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if (qversion < 0) {
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lgtrace_addp("quic version undefined %ld", -qversion);
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return -EPROTO;
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}
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lgtrace_addp("quic version valid %ld", qversion);
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if (left_len < 2) goto invalid_packet;
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struct quic_cids nqci = {0};
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nqci.dst_len = *cur_rawptr++;
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left_len--;
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if (left_len < nqci.dst_len) goto invalid_packet;
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nqci.dst_id = cur_rawptr;
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cur_rawptr += nqci.dst_len;
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left_len -= nqci.dst_len;
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nqci.src_len = *cur_rawptr++;
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left_len--;
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if (left_len < nqci.src_len) goto invalid_packet;
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nqci.src_id = cur_rawptr;
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cur_rawptr += nqci.src_len;
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left_len -= nqci.src_len;
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if (qch) *qch = nqch;
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if (qch_len) {
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*qch_len = sizeof(struct quic_lhdr) +
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nqci.src_len + nqci.dst_len;
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}
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if (qci) *qci = nqci;
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if (payload) *payload = cur_rawptr;
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if (plen) *plen = left_len;
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return 0;
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invalid_packet:
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return -EINVAL;
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}
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int quic_parse_initial_header(const uint8_t *inpayload, uint32_t inplen,
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struct quici_hdr *qhdr) {
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if (inplen < 3) goto invalid_packet;
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struct quici_hdr nqhdr;
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const uint8_t *cur_ptr = inpayload;
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uint32_t left_len = inplen;
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uint64_t tlen = left_len;
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nqhdr.token_len = quic_parse_varlength(cur_ptr, &tlen);
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nqhdr.token = cur_ptr + tlen;
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if (left_len < nqhdr.token_len + tlen)
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goto invalid_packet;
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cur_ptr += tlen + nqhdr.token_len;
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left_len -= tlen + nqhdr.token_len;
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tlen = left_len;
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nqhdr.length = quic_parse_varlength(cur_ptr, &tlen);
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if (left_len < nqhdr.length + tlen ||
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nqhdr.length < QUIC_SAMPLE_SIZE +
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QUIC_SAMPLE_OFFSET
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)
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goto invalid_packet;
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cur_ptr += tlen;
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nqhdr.protected_payload = cur_ptr;
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nqhdr.sample = cur_ptr + QUIC_SAMPLE_OFFSET;
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nqhdr.sample_length = QUIC_SAMPLE_SIZE;
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if (qhdr) *qhdr = nqhdr;
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return 0;
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invalid_packet:
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lgerror(-EINVAL, "QUIC invalid Initial packet");
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return -EINVAL;
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}
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int udp_fail_packet(struct udp_failing_strategy strategy, uint8_t *payload, uint32_t *plen, uint32_t avail_buflen) {
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void *iph;
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uint32_t iph_len;
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struct udphdr *udph;
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uint8_t *data;
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uint32_t dlen;
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int ret;
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ret = udp_payload_split(payload, *plen,
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&iph, &iph_len, &udph,
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&data, &dlen);
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uint32_t ipxv = netproto_version(payload, *plen);
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if (ret < 0) {
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return ret;
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}
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if (strategy.strategy == FAKE_STRAT_TTL) {
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lgtrace_addp("Set fake ttl to %d", strategy.faking_ttl);
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if (ipxv == IP4VERSION) {
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((struct iphdr *)iph)->ttl = strategy.faking_ttl;
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} else if (ipxv == IP6VERSION) {
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((struct ip6_hdr *)iph)->ip6_hops = strategy.faking_ttl;
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} else {
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lgerror(-EINVAL, "fail_packet: IP version is unsupported");
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return -EINVAL;
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}
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}
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if (ipxv == IP4VERSION) {
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((struct iphdr *)iph)->frag_off = 0;
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}
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set_ip_checksum(iph, iph_len);
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if (strategy.strategy == FAKE_STRAT_UDP_CHECK) {
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lgtrace_addp("break fake udp checksum");
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udph->check += 1;
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}
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return 0;
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}
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int gen_fake_udp(struct udp_fake_type type,
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const void *ipxh, uint32_t iph_len,
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const struct udphdr *udph,
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uint8_t *buf, uint32_t *buflen) {
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uint32_t data_len = type.fake_len;
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if (!ipxh || !udph || !buf || !buflen)
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return -EINVAL;
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int ipxv = netproto_version(ipxh, iph_len);
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if (ipxv == IP4VERSION) {
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const struct iphdr *iph = ipxh;
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memcpy(buf, iph, iph_len);
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struct iphdr *niph = (struct iphdr *)buf;
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niph->protocol = IPPROTO_UDP;
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} else if (ipxv == IP6VERSION) {
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const struct ip6_hdr *iph = ipxh;
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iph_len = sizeof(struct ip6_hdr);
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memcpy(buf, iph, iph_len);
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struct ip6_hdr *niph = (struct ip6_hdr *)buf;
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niph->ip6_nxt = IPPROTO_UDP;
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} else {
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return -EINVAL;
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}
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uint32_t dlen = iph_len + sizeof(struct udphdr) + data_len;
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if (*buflen < dlen)
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return -ENOMEM;
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memcpy(buf + iph_len, udph, sizeof(struct udphdr));
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uint8_t *bfdptr = buf + iph_len + sizeof(struct udphdr);
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memset(bfdptr, 0, data_len);
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if (ipxv == IP4VERSION) {
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struct iphdr *niph = (struct iphdr *)buf;
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niph->tot_len = htons(dlen);
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niph->id = randint();
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} else if (ipxv == IP6VERSION) {
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struct ip6_hdr *niph = (struct ip6_hdr *)buf;
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niph->ip6_plen = htons(dlen - iph_len);
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}
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struct udphdr *nudph = (struct udphdr *)(buf + iph_len);
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nudph->len = htons(sizeof(struct udphdr) + data_len);
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set_udp_checksum(nudph, buf, iph_len);
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udp_fail_packet(type.strategy, buf, &dlen, *buflen);
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*buflen = dlen;
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return 0;
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}
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int detect_udp_filtered(const struct section_config_t *section,
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const uint8_t *payload, uint32_t plen) {
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const void *iph;
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uint32_t iph_len;
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const struct udphdr *udph;
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const uint8_t *data;
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uint32_t dlen;
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int ret;
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ret = udp_payload_split((uint8_t *)payload, plen,
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(void **)&iph, &iph_len,
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(struct udphdr **)&udph,
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(uint8_t **)&data, &dlen);
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int udp_dport = ntohs(udph->dest);
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lgtrace_addp("UDP dport: %d", udp_dport);
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if (ret < 0) {
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goto skip;
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}
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if (section->udp_filter_quic) {
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const struct quic_lhdr *qch;
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uint32_t qch_len;
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struct quic_cids qci;
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const uint8_t *quic_raw_payload;
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uint32_t quic_raw_plen;
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lgtrace_addp("QUIC probe");
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ret = quic_parse_data((uint8_t *)data, dlen,
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&qch, &qch_len, &qci,
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&quic_raw_payload, &quic_raw_plen);
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if (ret < 0) {
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lgtrace_addp("QUIC undefined type");
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goto match_port;
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}
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lgtrace_addp("QUIC detected");
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uint8_t qtype = qch->type;
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if (qch->version == QUIC_V1)
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qtype = quic_convtype_v1(qtype);
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else if (qch->version == QUIC_V2)
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qtype = quic_convtype_v2(qtype);
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if (qtype != QUIC_INITIAL_TYPE) {
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lgtrace_addp("QUIC message type: %d", qtype);
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goto match_port;
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}
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lgtrace_addp("QUIC initial message");
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goto approve;
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}
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match_port:
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for (int i = 0; i < section->udp_dport_range_len; i++) {
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struct udp_dport_range crange = section->udp_dport_range[i];
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if (udp_dport >= crange.start && udp_dport <= crange.end) {
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lgtrace_addp("matched to %d-%d", crange.start, crange.end);
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goto approve;
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}
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}
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skip:
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return 0;
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approve:
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return 1;
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}
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