From: giulio-sido Date: Tue, 12 Oct 2021 15:17:58 +0000 (+0200) Subject: rt6: parse TLV X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/e69972a8ef1ddbf73924e42f76f53a1f9d0aab0a rt6: parse TLV Parse Type Length Values (TLV) in IPv6 Routing Header as specified by RFC 8754 [1]. [1] https://datatracker.ietf.org/doc/html/rfc8754 Signed-off-by: Giulio Sidoretti --- diff --git a/ip6.h b/ip6.h index f927d204..c4e2f484 100644 --- a/ip6.h +++ b/ip6.h @@ -197,6 +197,10 @@ struct ip6_srh { nd_ipv6 srh_segments[1]; /* SRH segments list*/ }; +#define IPV6_SRH_TLV_PAD1 0 +#define IPV6_SRH_TLV_PADN 4 +#define IPV6_SRH_TLV_HMAC 5 + /* Fragment header */ struct ip6_frag { nd_uint8_t ip6f_nxt; /* next header */ diff --git a/print-rt6.c b/print-rt6.c index 096a9628..82359a42 100644 --- a/print-rt6.c +++ b/print-rt6.c @@ -33,13 +33,95 @@ #include "ip6.h" +static int +srh_tlv_print(netdissect_options *ndo, const u_char *p, u_int bytes_left) +{ + u_int tlv_type, tlv_len; + while (bytes_left != 0) { + tlv_type = GET_U_1(p); + ND_ICHECKMSG_U("remaining length", bytes_left, <, 1); + p += 1; + bytes_left -= 1; + if (bytes_left == 0) + break; + if (tlv_type == IPV6_SRH_TLV_PAD1) { + ND_PRINT(", TLV-type=Pad1(%u)", tlv_type); + continue; + } + + tlv_len = GET_U_1(p); + ND_ICHECKMSG_U("remaining length", bytes_left, <, 1); + p += 1; + bytes_left -= 1; + + switch (tlv_type) { + case IPV6_SRH_TLV_PADN: + ND_PRINT(", TLV-type=PadN(%u)", tlv_type); + ND_PRINT(", TLV-len=%u", tlv_len); + ND_ICHECKMSG_U("PadN length", tlv_len, >, 5); /* RFC 8754 */ + ND_ICHECKMSG_U("remaining length", bytes_left, <, tlv_len); + p += tlv_len; + bytes_left -= tlv_len; + break; + case IPV6_SRH_TLV_HMAC: + ND_PRINT(", TLV-type=HMAC(%u)", tlv_type); + ND_PRINT(", TLV-len=%u", tlv_len); + ND_ICHECKMSG_U("remaining length", bytes_left, <, 6); + uint16_t reserved; + uint32_t key_id; + uint8_t hmac_byte; + reserved = GET_BE_U_2(p); + p += 2; + if (ndo->ndo_vflag) + ND_PRINT(", D=%u", reserved >> 15); + key_id = GET_BE_U_4(p); + p += 4; + if (ndo->ndo_vflag) + ND_PRINT(", HMAC-key-ID=0x%02x", key_id); + bytes_left -= 6; + if (ndo->ndo_vflag) + ND_PRINT(", HMAC=0x"); + for (u_int i = 0; i < tlv_len; i++) { + hmac_byte = GET_U_1(p); + ND_ICHECKMSG_U("remaining length", bytes_left, <, 1); + p += 1; + bytes_left -= 1; + if (ndo->ndo_vflag) + ND_PRINT("%02x", hmac_byte); + } + break; + default: /* Unknown type */ + ND_PRINT(" Unknown"); + ND_PRINT(", TLV-len=%u", tlv_len); + if (ndo->ndo_vflag) + ND_PRINT(", TLV-value=0x"); + ND_ICHECKMSG_U("remaining length", bytes_left, <, tlv_len); + uint8_t tlv_byte; + for (u_int i = 0; i < tlv_len; i++) { + tlv_byte = GET_U_1(p); + p += 1; + bytes_left -= 1; + if (ndo->ndo_vflag) + ND_PRINT("%02x", tlv_byte); + } + break; + } + } + return 0; + +invalid: + return -1; +} + + int rt6_print(netdissect_options *ndo, const u_char *bp, const u_char *bp2 _U_) { const struct ip6_rthdr *dp; const struct ip6_rthdr0 *dp0; const struct ip6_srh *srh; - u_int i, len, type; + u_int i, len, type, seg_list_len, last_entry; + int err; const u_char *p; ndo->ndo_protocol = "rt6"; @@ -81,7 +163,8 @@ rt6_print(netdissect_options *ndo, const u_char *bp, const u_char *bp2 _U_) break; case IPV6_RTHDR_TYPE_4: srh = (const struct ip6_srh *)dp; - ND_PRINT(", last-entry=%u", GET_U_1(srh->srh_last_ent)); + last_entry = GET_U_1(srh->srh_last_ent); + ND_PRINT(", last-entry=%u", last_entry); if (GET_U_1(srh->srh_flags) || ndo->ndo_vflag) { ND_PRINT(", flags=0x%0x", @@ -89,17 +172,21 @@ rt6_print(netdissect_options *ndo, const u_char *bp, const u_char *bp2 _U_) } ND_PRINT(", tag=%x", GET_BE_U_2(srh->srh_tag)); - - if (len % 2 == 1) { - ND_PRINT(" (invalid length %u)", len); - goto invalid; - } - len >>= 1; p = (const u_char *) srh->srh_segments; - for (i = 0; i < len; i++) { + for (i = 0; i < last_entry + 1; i++) { ND_PRINT(", [%u]%s", i, GET_IP6ADDR_STRING(p)); p += 16; } + seg_list_len = (last_entry + 1) * 2; + if (seg_list_len < len) { + /* there is TLV */ + u_int bytes_left; + bytes_left = (len - seg_list_len) * 8; + err = srh_tlv_print(ndo, p, bytes_left); + if (err) + goto invalid; + } + /*(*/ ND_PRINT(") "); return((GET_U_1(srh->srh_len) + 1) << 3); diff --git a/tests/TESTLIST b/tests/TESTLIST index 95592bd6..46babe8d 100644 --- a/tests/TESTLIST +++ b/tests/TESTLIST @@ -349,6 +349,10 @@ ipv6-srh-ipproto-ether-v ipv6-srh-ipproto-ether.pcap ipv6-srh-ipproto-ether-v.ou ipv6-srh-ipproto-ether-ev ipv6-srh-ipproto-ether.pcap ipv6-srh-ipproto-ether-ev.out -ev ipv6-too-long-jumbo ipv6-too-long-jumbo.pcap ipv6-too-long-jumbo.out -v ipv6_jumbogram_1 ipv6_jumbogram_1.pcap ipv6_jumbogram_1.out -ev +ipv6-srh-tlv-hmac ipv6-srh-tlv-hmac.pcap ipv6-srh-tlv-hmac.out +ipv6-srh-tlv-hmac-v ipv6-srh-tlv-hmac.pcap ipv6-srh-tlv-hmac-v.out -v +ipv6-srh-tlv-pad1-padn-5 ipv6-srh-tlv-pad1-padn-5.pcap ipv6-srh-tlv-pad1-padn-5.out +ipv6-srh-tlv-pad1-padn-5-v ipv6-srh-tlv-pad1-padn-5.pcap ipv6-srh-tlv-pad1-padn-5-v.out -v # Loopback/CTP test case loopback loopback.pcap loopback.out diff --git a/tests/ipv6-srh-tlv-hmac-v.out b/tests/ipv6-srh-tlv-hmac-v.out new file mode 100644 index 00000000..29da7a2d --- /dev/null +++ b/tests/ipv6-srh-tlv-hmac-v.out @@ -0,0 +1 @@ + 1 09:28:06.000000 IP6 (class 0x78, flowlabel 0x9abcd, hlim 64, next-header Routing (43) payload length: 48) 2001:db8:1::1 > cafe:1::2: RT6 (len=5, type=4, segleft=0, last-entry=0, flags=0x0, tag=0, [0]cafe:1::2, TLV-type=HMAC(5), TLV-len=16, D=1, HMAC-key-ID=0x5412ab30, HMAC=0x0000000000000000aaaaaaaaaaaaaaaa) no next header diff --git a/tests/ipv6-srh-tlv-hmac.out b/tests/ipv6-srh-tlv-hmac.out new file mode 100644 index 00000000..a64f2079 --- /dev/null +++ b/tests/ipv6-srh-tlv-hmac.out @@ -0,0 +1 @@ + 1 09:28:06.000000 IP6 2001:db8:1::1 > cafe:1::2: RT6 (len=5, type=4, segleft=0, last-entry=0, tag=0, [0]cafe:1::2, TLV-type=HMAC(5), TLV-len=16) no next header diff --git a/tests/ipv6-srh-tlv-hmac.pcap b/tests/ipv6-srh-tlv-hmac.pcap new file mode 100644 index 00000000..3333e00a Binary files /dev/null and b/tests/ipv6-srh-tlv-hmac.pcap differ diff --git a/tests/ipv6-srh-tlv-pad1-padn-5-v.out b/tests/ipv6-srh-tlv-pad1-padn-5-v.out new file mode 100644 index 00000000..fd0fc47f --- /dev/null +++ b/tests/ipv6-srh-tlv-pad1-padn-5-v.out @@ -0,0 +1 @@ + 1 17:47:55.000001 IP6 (class 0x78, flowlabel 0x9abcd, hlim 64, next-header Routing (43) payload length: 32) 2001:db8:1::1 > cafe:1::2: RT6 (len=3, type=4, segleft=0, last-entry=0, flags=0x0, tag=0, [0]cafe:1::2, TLV-type=Pad1(0), TLV-type=PadN(4), TLV-len=5) no next header diff --git a/tests/ipv6-srh-tlv-pad1-padn-5.out b/tests/ipv6-srh-tlv-pad1-padn-5.out new file mode 100644 index 00000000..a2af4a61 --- /dev/null +++ b/tests/ipv6-srh-tlv-pad1-padn-5.out @@ -0,0 +1 @@ + 1 17:47:55.000001 IP6 2001:db8:1::1 > cafe:1::2: RT6 (len=3, type=4, segleft=0, last-entry=0, tag=0, [0]cafe:1::2, TLV-type=Pad1(0), TLV-type=PadN(4), TLV-len=5) no next header diff --git a/tests/ipv6-srh-tlv-pad1-padn-5.pcap b/tests/ipv6-srh-tlv-pad1-padn-5.pcap new file mode 100644 index 00000000..ba8fe6e8 Binary files /dev/null and b/tests/ipv6-srh-tlv-pad1-padn-5.pcap differ