1544 lines
43 KiB
C
1544 lines
43 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Multipath TCP
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*
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* Copyright (c) 2017 - 2019, Intel Corporation.
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*/
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#define pr_fmt(fmt) "MPTCP: " fmt
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#include <linux/kernel.h>
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#include <crypto/sha2.h>
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#include <net/tcp.h>
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#include <net/mptcp.h>
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#include "protocol.h"
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#include "mib.h"
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#include <trace/events/mptcp.h>
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static bool mptcp_cap_flag_sha256(u8 flags)
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{
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return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256;
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}
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static void mptcp_parse_option(const struct sk_buff *skb,
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const unsigned char *ptr, int opsize,
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struct mptcp_options_received *mp_opt)
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{
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u8 subtype = *ptr >> 4;
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int expected_opsize;
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u8 version;
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u8 flags;
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u8 i;
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switch (subtype) {
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case MPTCPOPT_MP_CAPABLE:
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/* strict size checking */
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if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
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if (skb->len > tcp_hdr(skb)->doff << 2)
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expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA;
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else
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expected_opsize = TCPOLEN_MPTCP_MPC_ACK;
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} else {
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if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK)
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expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK;
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else
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expected_opsize = TCPOLEN_MPTCP_MPC_SYN;
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}
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/* Cfr RFC 8684 Section 3.3.0:
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* If a checksum is present but its use had
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* not been negotiated in the MP_CAPABLE handshake, the receiver MUST
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* close the subflow with a RST, as it is not behaving as negotiated.
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* If a checksum is not present when its use has been negotiated, the
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* receiver MUST close the subflow with a RST, as it is considered
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* broken
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* We parse even option with mismatching csum presence, so that
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* later in subflow_data_ready we can trigger the reset.
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*/
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if (opsize != expected_opsize &&
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(expected_opsize != TCPOLEN_MPTCP_MPC_ACK_DATA ||
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opsize != TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM))
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break;
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/* try to be gentle vs future versions on the initial syn */
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version = *ptr++ & MPTCP_VERSION_MASK;
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if (opsize != TCPOLEN_MPTCP_MPC_SYN) {
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if (version != MPTCP_SUPPORTED_VERSION)
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break;
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} else if (version < MPTCP_SUPPORTED_VERSION) {
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break;
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}
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flags = *ptr++;
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if (!mptcp_cap_flag_sha256(flags) ||
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(flags & MPTCP_CAP_EXTENSIBILITY))
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break;
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/* RFC 6824, Section 3.1:
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* "For the Checksum Required bit (labeled "A"), if either
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* host requires the use of checksums, checksums MUST be used.
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* In other words, the only way for checksums not to be used
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* is if both hosts in their SYNs set A=0."
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*/
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if (flags & MPTCP_CAP_CHECKSUM_REQD)
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mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD;
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mp_opt->deny_join_id0 = !!(flags & MPTCP_CAP_DENY_JOIN_ID0);
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mp_opt->suboptions |= OPTIONS_MPTCP_MPC;
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if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) {
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mp_opt->sndr_key = get_unaligned_be64(ptr);
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ptr += 8;
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}
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if (opsize >= TCPOLEN_MPTCP_MPC_ACK) {
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mp_opt->rcvr_key = get_unaligned_be64(ptr);
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ptr += 8;
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}
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if (opsize >= TCPOLEN_MPTCP_MPC_ACK_DATA) {
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/* Section 3.1.:
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* "the data parameters in a MP_CAPABLE are semantically
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* equivalent to those in a DSS option and can be used
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* interchangeably."
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*/
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mp_opt->suboptions |= OPTION_MPTCP_DSS;
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mp_opt->use_map = 1;
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mp_opt->mpc_map = 1;
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mp_opt->data_len = get_unaligned_be16(ptr);
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ptr += 2;
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}
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if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM) {
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mp_opt->csum = (__force __sum16)get_unaligned_be16(ptr);
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mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD;
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ptr += 2;
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}
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pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d csum=%u",
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version, flags, opsize, mp_opt->sndr_key,
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mp_opt->rcvr_key, mp_opt->data_len, mp_opt->csum);
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break;
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case MPTCPOPT_MP_JOIN:
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mp_opt->suboptions |= OPTIONS_MPTCP_MPJ;
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if (opsize == TCPOLEN_MPTCP_MPJ_SYN) {
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mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP;
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mp_opt->join_id = *ptr++;
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mp_opt->token = get_unaligned_be32(ptr);
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ptr += 4;
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mp_opt->nonce = get_unaligned_be32(ptr);
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ptr += 4;
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pr_debug("MP_JOIN bkup=%u, id=%u, token=%u, nonce=%u",
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mp_opt->backup, mp_opt->join_id,
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mp_opt->token, mp_opt->nonce);
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} else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) {
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mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP;
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mp_opt->join_id = *ptr++;
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mp_opt->thmac = get_unaligned_be64(ptr);
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ptr += 8;
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mp_opt->nonce = get_unaligned_be32(ptr);
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ptr += 4;
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pr_debug("MP_JOIN bkup=%u, id=%u, thmac=%llu, nonce=%u",
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mp_opt->backup, mp_opt->join_id,
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mp_opt->thmac, mp_opt->nonce);
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} else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) {
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ptr += 2;
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memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN);
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pr_debug("MP_JOIN hmac");
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} else {
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mp_opt->suboptions &= ~OPTIONS_MPTCP_MPJ;
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}
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break;
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case MPTCPOPT_DSS:
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pr_debug("DSS");
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ptr++;
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/* we must clear 'mpc_map' be able to detect MP_CAPABLE
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* map vs DSS map in mptcp_incoming_options(), and reconstruct
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* map info accordingly
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*/
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mp_opt->mpc_map = 0;
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flags = (*ptr++) & MPTCP_DSS_FLAG_MASK;
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mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0;
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mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0;
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mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0;
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mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0;
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mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK);
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pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d",
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mp_opt->data_fin, mp_opt->dsn64,
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mp_opt->use_map, mp_opt->ack64,
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mp_opt->use_ack);
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expected_opsize = TCPOLEN_MPTCP_DSS_BASE;
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if (mp_opt->use_ack) {
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if (mp_opt->ack64)
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expected_opsize += TCPOLEN_MPTCP_DSS_ACK64;
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else
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expected_opsize += TCPOLEN_MPTCP_DSS_ACK32;
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}
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if (mp_opt->use_map) {
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if (mp_opt->dsn64)
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expected_opsize += TCPOLEN_MPTCP_DSS_MAP64;
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else
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expected_opsize += TCPOLEN_MPTCP_DSS_MAP32;
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}
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/* Always parse any csum presence combination, we will enforce
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* RFC 8684 Section 3.3.0 checks later in subflow_data_ready
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*/
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if (opsize != expected_opsize &&
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opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM)
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break;
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mp_opt->suboptions |= OPTION_MPTCP_DSS;
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if (mp_opt->use_ack) {
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if (mp_opt->ack64) {
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mp_opt->data_ack = get_unaligned_be64(ptr);
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ptr += 8;
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} else {
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mp_opt->data_ack = get_unaligned_be32(ptr);
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ptr += 4;
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}
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pr_debug("data_ack=%llu", mp_opt->data_ack);
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}
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if (mp_opt->use_map) {
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if (mp_opt->dsn64) {
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mp_opt->data_seq = get_unaligned_be64(ptr);
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ptr += 8;
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} else {
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mp_opt->data_seq = get_unaligned_be32(ptr);
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ptr += 4;
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}
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mp_opt->subflow_seq = get_unaligned_be32(ptr);
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ptr += 4;
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mp_opt->data_len = get_unaligned_be16(ptr);
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ptr += 2;
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if (opsize == expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) {
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mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD;
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mp_opt->csum = (__force __sum16)get_unaligned_be16(ptr);
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ptr += 2;
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}
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pr_debug("data_seq=%llu subflow_seq=%u data_len=%u csum=%d:%u",
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mp_opt->data_seq, mp_opt->subflow_seq,
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mp_opt->data_len, !!(mp_opt->suboptions & OPTION_MPTCP_CSUMREQD),
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mp_opt->csum);
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}
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break;
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case MPTCPOPT_ADD_ADDR:
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mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO;
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if (!mp_opt->echo) {
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if (opsize == TCPOLEN_MPTCP_ADD_ADDR ||
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opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT)
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mp_opt->addr.family = AF_INET;
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#if IS_ENABLED(CONFIG_MPTCP_IPV6)
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else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 ||
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opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT)
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mp_opt->addr.family = AF_INET6;
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#endif
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else
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break;
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} else {
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if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE ||
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opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT)
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mp_opt->addr.family = AF_INET;
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#if IS_ENABLED(CONFIG_MPTCP_IPV6)
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else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE ||
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opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT)
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mp_opt->addr.family = AF_INET6;
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#endif
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else
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break;
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}
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mp_opt->suboptions |= OPTION_MPTCP_ADD_ADDR;
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mp_opt->addr.id = *ptr++;
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mp_opt->addr.port = 0;
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mp_opt->ahmac = 0;
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if (mp_opt->addr.family == AF_INET) {
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memcpy((u8 *)&mp_opt->addr.addr.s_addr, (u8 *)ptr, 4);
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ptr += 4;
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if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT ||
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opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) {
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mp_opt->addr.port = htons(get_unaligned_be16(ptr));
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ptr += 2;
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}
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}
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#if IS_ENABLED(CONFIG_MPTCP_IPV6)
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else {
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memcpy(mp_opt->addr.addr6.s6_addr, (u8 *)ptr, 16);
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ptr += 16;
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if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT ||
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opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) {
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mp_opt->addr.port = htons(get_unaligned_be16(ptr));
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ptr += 2;
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}
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}
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#endif
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if (!mp_opt->echo) {
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mp_opt->ahmac = get_unaligned_be64(ptr);
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ptr += 8;
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}
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pr_debug("ADD_ADDR%s: id=%d, ahmac=%llu, echo=%d, port=%d",
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(mp_opt->addr.family == AF_INET6) ? "6" : "",
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mp_opt->addr.id, mp_opt->ahmac, mp_opt->echo, ntohs(mp_opt->addr.port));
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break;
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case MPTCPOPT_RM_ADDR:
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if (opsize < TCPOLEN_MPTCP_RM_ADDR_BASE + 1 ||
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opsize > TCPOLEN_MPTCP_RM_ADDR_BASE + MPTCP_RM_IDS_MAX)
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break;
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ptr++;
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mp_opt->suboptions |= OPTION_MPTCP_RM_ADDR;
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mp_opt->rm_list.nr = opsize - TCPOLEN_MPTCP_RM_ADDR_BASE;
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for (i = 0; i < mp_opt->rm_list.nr; i++)
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mp_opt->rm_list.ids[i] = *ptr++;
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pr_debug("RM_ADDR: rm_list_nr=%d", mp_opt->rm_list.nr);
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break;
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case MPTCPOPT_MP_PRIO:
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if (opsize != TCPOLEN_MPTCP_PRIO)
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break;
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mp_opt->suboptions |= OPTION_MPTCP_PRIO;
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mp_opt->backup = *ptr++ & MPTCP_PRIO_BKUP;
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pr_debug("MP_PRIO: prio=%d", mp_opt->backup);
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break;
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case MPTCPOPT_MP_FASTCLOSE:
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if (opsize != TCPOLEN_MPTCP_FASTCLOSE)
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break;
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ptr += 2;
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mp_opt->rcvr_key = get_unaligned_be64(ptr);
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ptr += 8;
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mp_opt->suboptions |= OPTION_MPTCP_FASTCLOSE;
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break;
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case MPTCPOPT_RST:
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if (opsize != TCPOLEN_MPTCP_RST)
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break;
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if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST))
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break;
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mp_opt->suboptions |= OPTION_MPTCP_RST;
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flags = *ptr++;
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mp_opt->reset_transient = flags & MPTCP_RST_TRANSIENT;
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mp_opt->reset_reason = *ptr;
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break;
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case MPTCPOPT_MP_FAIL:
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if (opsize != TCPOLEN_MPTCP_FAIL)
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break;
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ptr += 2;
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mp_opt->suboptions |= OPTION_MPTCP_FAIL;
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mp_opt->fail_seq = get_unaligned_be64(ptr);
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pr_debug("MP_FAIL: data_seq=%llu", mp_opt->fail_seq);
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break;
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default:
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break;
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}
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}
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void mptcp_get_options(const struct sock *sk,
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const struct sk_buff *skb,
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struct mptcp_options_received *mp_opt)
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{
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const struct tcphdr *th = tcp_hdr(skb);
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const unsigned char *ptr;
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int length;
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/* initialize option status */
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mp_opt->suboptions = 0;
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length = (th->doff * 4) - sizeof(struct tcphdr);
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ptr = (const unsigned char *)(th + 1);
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while (length > 0) {
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int opcode = *ptr++;
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int opsize;
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switch (opcode) {
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case TCPOPT_EOL:
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return;
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case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */
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length--;
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continue;
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default:
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if (length < 2)
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return;
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opsize = *ptr++;
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if (opsize < 2) /* "silly options" */
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return;
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if (opsize > length)
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return; /* don't parse partial options */
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if (opcode == TCPOPT_MPTCP)
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mptcp_parse_option(skb, ptr, opsize, mp_opt);
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ptr += opsize - 2;
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length -= opsize;
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}
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}
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}
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bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
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unsigned int *size, struct mptcp_out_options *opts)
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{
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
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/* we will use snd_isn to detect first pkt [re]transmission
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* in mptcp_established_options_mp()
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*/
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subflow->snd_isn = TCP_SKB_CB(skb)->end_seq;
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if (subflow->request_mptcp) {
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opts->suboptions = OPTION_MPTCP_MPC_SYN;
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opts->csum_reqd = mptcp_is_checksum_enabled(sock_net(sk));
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opts->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk));
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*size = TCPOLEN_MPTCP_MPC_SYN;
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return true;
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} else if (subflow->request_join) {
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pr_debug("remote_token=%u, nonce=%u", subflow->remote_token,
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subflow->local_nonce);
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opts->suboptions = OPTION_MPTCP_MPJ_SYN;
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opts->join_id = subflow->local_id;
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opts->token = subflow->remote_token;
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opts->nonce = subflow->local_nonce;
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opts->backup = subflow->request_bkup;
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*size = TCPOLEN_MPTCP_MPJ_SYN;
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return true;
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}
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return false;
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}
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static void clear_3rdack_retransmission(struct sock *sk)
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{
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struct inet_connection_sock *icsk = inet_csk(sk);
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sk_stop_timer(sk, &icsk->icsk_delack_timer);
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icsk->icsk_ack.timeout = 0;
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icsk->icsk_ack.ato = 0;
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icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER);
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}
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static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
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bool snd_data_fin_enable,
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unsigned int *size,
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unsigned int remaining,
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struct mptcp_out_options *opts)
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{
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struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
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struct mptcp_sock *msk = mptcp_sk(subflow->conn);
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struct mptcp_ext *mpext;
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unsigned int data_len;
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u8 len;
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/* When skb is not available, we better over-estimate the emitted
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* options len. A full DSS option (28 bytes) is longer than
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* TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so
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* tell the caller to defer the estimate to
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* mptcp_established_options_dss(), which will reserve enough space.
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*/
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if (!skb)
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return false;
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/* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */
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if (subflow->fully_established || snd_data_fin_enable ||
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|
subflow->snd_isn != TCP_SKB_CB(skb)->seq ||
|
|
sk->sk_state != TCP_ESTABLISHED)
|
|
return false;
|
|
|
|
if (subflow->mp_capable) {
|
|
mpext = mptcp_get_ext(skb);
|
|
data_len = mpext ? mpext->data_len : 0;
|
|
|
|
/* we will check ops->data_len in mptcp_write_options() to
|
|
* discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and
|
|
* TCPOLEN_MPTCP_MPC_ACK
|
|
*/
|
|
opts->data_len = data_len;
|
|
opts->suboptions = OPTION_MPTCP_MPC_ACK;
|
|
opts->sndr_key = subflow->local_key;
|
|
opts->rcvr_key = subflow->remote_key;
|
|
opts->csum_reqd = READ_ONCE(msk->csum_enabled);
|
|
opts->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk));
|
|
|
|
/* Section 3.1.
|
|
* The MP_CAPABLE option is carried on the SYN, SYN/ACK, and ACK
|
|
* packets that start the first subflow of an MPTCP connection,
|
|
* as well as the first packet that carries data
|
|
*/
|
|
if (data_len > 0) {
|
|
len = TCPOLEN_MPTCP_MPC_ACK_DATA;
|
|
if (opts->csum_reqd) {
|
|
/* we need to propagate more info to csum the pseudo hdr */
|
|
opts->data_seq = mpext->data_seq;
|
|
opts->subflow_seq = mpext->subflow_seq;
|
|
opts->csum = mpext->csum;
|
|
len += TCPOLEN_MPTCP_DSS_CHECKSUM;
|
|
}
|
|
*size = ALIGN(len, 4);
|
|
} else {
|
|
*size = TCPOLEN_MPTCP_MPC_ACK;
|
|
}
|
|
|
|
pr_debug("subflow=%p, local_key=%llu, remote_key=%llu map_len=%d",
|
|
subflow, subflow->local_key, subflow->remote_key,
|
|
data_len);
|
|
|
|
return true;
|
|
} else if (subflow->mp_join) {
|
|
opts->suboptions = OPTION_MPTCP_MPJ_ACK;
|
|
memcpy(opts->hmac, subflow->hmac, MPTCPOPT_HMAC_LEN);
|
|
*size = TCPOLEN_MPTCP_MPJ_ACK;
|
|
pr_debug("subflow=%p", subflow);
|
|
|
|
/* we can use the full delegate action helper only from BH context
|
|
* If we are in process context - sk is flushing the backlog at
|
|
* socket lock release time - just set the appropriate flag, will
|
|
* be handled by the release callback
|
|
*/
|
|
if (sock_owned_by_user(sk))
|
|
set_bit(MPTCP_DELEGATE_ACK, &subflow->delegated_status);
|
|
else
|
|
mptcp_subflow_delegate(subflow, MPTCP_DELEGATE_ACK);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow,
|
|
struct sk_buff *skb, struct mptcp_ext *ext)
|
|
{
|
|
/* The write_seq value has already been incremented, so the actual
|
|
* sequence number for the DATA_FIN is one less.
|
|
*/
|
|
u64 data_fin_tx_seq = READ_ONCE(mptcp_sk(subflow->conn)->write_seq) - 1;
|
|
|
|
if (!ext->use_map || !skb->len) {
|
|
/* RFC6824 requires a DSS mapping with specific values
|
|
* if DATA_FIN is set but no data payload is mapped
|
|
*/
|
|
ext->data_fin = 1;
|
|
ext->use_map = 1;
|
|
ext->dsn64 = 1;
|
|
ext->data_seq = data_fin_tx_seq;
|
|
ext->subflow_seq = 0;
|
|
ext->data_len = 1;
|
|
} else if (ext->data_seq + ext->data_len == data_fin_tx_seq) {
|
|
/* If there's an existing DSS mapping and it is the
|
|
* final mapping, DATA_FIN consumes 1 additional byte of
|
|
* mapping space.
|
|
*/
|
|
ext->data_fin = 1;
|
|
ext->data_len++;
|
|
}
|
|
}
|
|
|
|
static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
|
|
bool snd_data_fin_enable,
|
|
unsigned int *size,
|
|
unsigned int remaining,
|
|
struct mptcp_out_options *opts)
|
|
{
|
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
|
|
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
|
|
unsigned int dss_size = 0;
|
|
struct mptcp_ext *mpext;
|
|
unsigned int ack_size;
|
|
bool ret = false;
|
|
u64 ack_seq;
|
|
|
|
opts->csum_reqd = READ_ONCE(msk->csum_enabled);
|
|
mpext = skb ? mptcp_get_ext(skb) : NULL;
|
|
|
|
if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) {
|
|
unsigned int map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
|
|
|
|
if (mpext) {
|
|
if (opts->csum_reqd)
|
|
map_size += TCPOLEN_MPTCP_DSS_CHECKSUM;
|
|
|
|
opts->ext_copy = *mpext;
|
|
}
|
|
|
|
remaining -= map_size;
|
|
dss_size = map_size;
|
|
if (skb && snd_data_fin_enable)
|
|
mptcp_write_data_fin(subflow, skb, &opts->ext_copy);
|
|
opts->suboptions = OPTION_MPTCP_DSS;
|
|
ret = true;
|
|
}
|
|
|
|
/* passive sockets msk will set the 'can_ack' after accept(), even
|
|
* if the first subflow may have the already the remote key handy
|
|
*/
|
|
opts->ext_copy.use_ack = 0;
|
|
if (!READ_ONCE(msk->can_ack)) {
|
|
*size = ALIGN(dss_size, 4);
|
|
return ret;
|
|
}
|
|
|
|
ack_seq = READ_ONCE(msk->ack_seq);
|
|
if (READ_ONCE(msk->use_64bit_ack)) {
|
|
ack_size = TCPOLEN_MPTCP_DSS_ACK64;
|
|
opts->ext_copy.data_ack = ack_seq;
|
|
opts->ext_copy.ack64 = 1;
|
|
} else {
|
|
ack_size = TCPOLEN_MPTCP_DSS_ACK32;
|
|
opts->ext_copy.data_ack32 = (uint32_t)ack_seq;
|
|
opts->ext_copy.ack64 = 0;
|
|
}
|
|
opts->ext_copy.use_ack = 1;
|
|
opts->suboptions = OPTION_MPTCP_DSS;
|
|
WRITE_ONCE(msk->old_wspace, __mptcp_space((struct sock *)msk));
|
|
|
|
/* Add kind/length/subtype/flag overhead if mapping is not populated */
|
|
if (dss_size == 0)
|
|
ack_size += TCPOLEN_MPTCP_DSS_BASE;
|
|
|
|
dss_size += ack_size;
|
|
|
|
*size = ALIGN(dss_size, 4);
|
|
return true;
|
|
}
|
|
|
|
static u64 add_addr_generate_hmac(u64 key1, u64 key2,
|
|
struct mptcp_addr_info *addr)
|
|
{
|
|
u16 port = ntohs(addr->port);
|
|
u8 hmac[SHA256_DIGEST_SIZE];
|
|
u8 msg[19];
|
|
int i = 0;
|
|
|
|
msg[i++] = addr->id;
|
|
if (addr->family == AF_INET) {
|
|
memcpy(&msg[i], &addr->addr.s_addr, 4);
|
|
i += 4;
|
|
}
|
|
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
|
|
else if (addr->family == AF_INET6) {
|
|
memcpy(&msg[i], &addr->addr6.s6_addr, 16);
|
|
i += 16;
|
|
}
|
|
#endif
|
|
msg[i++] = port >> 8;
|
|
msg[i++] = port & 0xFF;
|
|
|
|
mptcp_crypto_hmac_sha(key1, key2, msg, i, hmac);
|
|
|
|
return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
|
|
}
|
|
|
|
static bool mptcp_established_options_add_addr(struct sock *sk, struct sk_buff *skb,
|
|
unsigned int *size,
|
|
unsigned int remaining,
|
|
struct mptcp_out_options *opts)
|
|
{
|
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
|
|
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
|
|
bool drop_other_suboptions = false;
|
|
unsigned int opt_size = *size;
|
|
bool echo;
|
|
bool port;
|
|
int len;
|
|
|
|
/* add addr will strip the existing options, be sure to avoid breaking
|
|
* MPC/MPJ handshakes
|
|
*/
|
|
if (!mptcp_pm_should_add_signal(msk) ||
|
|
(opts->suboptions & (OPTION_MPTCP_MPJ_ACK | OPTION_MPTCP_MPC_ACK)) ||
|
|
!mptcp_pm_add_addr_signal(msk, skb, opt_size, remaining, &opts->addr,
|
|
&echo, &port, &drop_other_suboptions))
|
|
return false;
|
|
|
|
if (drop_other_suboptions)
|
|
remaining += opt_size;
|
|
len = mptcp_add_addr_len(opts->addr.family, echo, port);
|
|
if (remaining < len)
|
|
return false;
|
|
|
|
*size = len;
|
|
if (drop_other_suboptions) {
|
|
pr_debug("drop other suboptions");
|
|
opts->suboptions = 0;
|
|
|
|
/* note that e.g. DSS could have written into the memory
|
|
* aliased by ahmac, we must reset the field here
|
|
* to avoid appending the hmac even for ADD_ADDR echo
|
|
* options
|
|
*/
|
|
opts->ahmac = 0;
|
|
*size -= opt_size;
|
|
}
|
|
opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
|
|
if (!echo) {
|
|
opts->ahmac = add_addr_generate_hmac(msk->local_key,
|
|
msk->remote_key,
|
|
&opts->addr);
|
|
}
|
|
pr_debug("addr_id=%d, ahmac=%llu, echo=%d, port=%d",
|
|
opts->addr.id, opts->ahmac, echo, ntohs(opts->addr.port));
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool mptcp_established_options_rm_addr(struct sock *sk,
|
|
unsigned int *size,
|
|
unsigned int remaining,
|
|
struct mptcp_out_options *opts)
|
|
{
|
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
|
|
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
|
|
struct mptcp_rm_list rm_list;
|
|
int i, len;
|
|
|
|
if (!mptcp_pm_should_rm_signal(msk) ||
|
|
!(mptcp_pm_rm_addr_signal(msk, remaining, &rm_list)))
|
|
return false;
|
|
|
|
len = mptcp_rm_addr_len(&rm_list);
|
|
if (len < 0)
|
|
return false;
|
|
if (remaining < len)
|
|
return false;
|
|
|
|
*size = len;
|
|
opts->suboptions |= OPTION_MPTCP_RM_ADDR;
|
|
opts->rm_list = rm_list;
|
|
|
|
for (i = 0; i < opts->rm_list.nr; i++)
|
|
pr_debug("rm_list_ids[%d]=%d", i, opts->rm_list.ids[i]);
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool mptcp_established_options_mp_prio(struct sock *sk,
|
|
unsigned int *size,
|
|
unsigned int remaining,
|
|
struct mptcp_out_options *opts)
|
|
{
|
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
|
|
|
|
/* can't send MP_PRIO with MPC, as they share the same option space:
|
|
* 'backup'. Also it makes no sense at all
|
|
*/
|
|
if (!subflow->send_mp_prio || (opts->suboptions & OPTIONS_MPTCP_MPC))
|
|
return false;
|
|
|
|
/* account for the trailing 'nop' option */
|
|
if (remaining < TCPOLEN_MPTCP_PRIO_ALIGN)
|
|
return false;
|
|
|
|
*size = TCPOLEN_MPTCP_PRIO_ALIGN;
|
|
opts->suboptions |= OPTION_MPTCP_PRIO;
|
|
opts->backup = subflow->request_bkup;
|
|
|
|
pr_debug("prio=%d", opts->backup);
|
|
|
|
return true;
|
|
}
|
|
|
|
static noinline bool mptcp_established_options_rst(struct sock *sk, struct sk_buff *skb,
|
|
unsigned int *size,
|
|
unsigned int remaining,
|
|
struct mptcp_out_options *opts)
|
|
{
|
|
const struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
|
|
|
|
if (remaining < TCPOLEN_MPTCP_RST)
|
|
return false;
|
|
|
|
*size = TCPOLEN_MPTCP_RST;
|
|
opts->suboptions |= OPTION_MPTCP_RST;
|
|
opts->reset_transient = subflow->reset_transient;
|
|
opts->reset_reason = subflow->reset_reason;
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool mptcp_established_options_fastclose(struct sock *sk,
|
|
unsigned int *size,
|
|
unsigned int remaining,
|
|
struct mptcp_out_options *opts)
|
|
{
|
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
|
|
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
|
|
|
|
if (likely(!subflow->send_fastclose))
|
|
return false;
|
|
|
|
if (remaining < TCPOLEN_MPTCP_FASTCLOSE)
|
|
return false;
|
|
|
|
*size = TCPOLEN_MPTCP_FASTCLOSE;
|
|
opts->suboptions |= OPTION_MPTCP_FASTCLOSE;
|
|
opts->rcvr_key = msk->remote_key;
|
|
|
|
pr_debug("FASTCLOSE key=%llu", opts->rcvr_key);
|
|
return true;
|
|
}
|
|
|
|
static bool mptcp_established_options_mp_fail(struct sock *sk,
|
|
unsigned int *size,
|
|
unsigned int remaining,
|
|
struct mptcp_out_options *opts)
|
|
{
|
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
|
|
|
|
if (likely(!subflow->send_mp_fail))
|
|
return false;
|
|
|
|
if (remaining < TCPOLEN_MPTCP_FAIL)
|
|
return false;
|
|
|
|
*size = TCPOLEN_MPTCP_FAIL;
|
|
opts->suboptions |= OPTION_MPTCP_FAIL;
|
|
opts->fail_seq = subflow->map_seq;
|
|
|
|
pr_debug("MP_FAIL fail_seq=%llu", opts->fail_seq);
|
|
|
|
return true;
|
|
}
|
|
|
|
bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
|
|
unsigned int *size, unsigned int remaining,
|
|
struct mptcp_out_options *opts)
|
|
{
|
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
|
|
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
|
|
unsigned int opt_size = 0;
|
|
bool snd_data_fin;
|
|
bool ret = false;
|
|
|
|
opts->suboptions = 0;
|
|
|
|
if (unlikely(__mptcp_check_fallback(msk)))
|
|
return false;
|
|
|
|
if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) {
|
|
if (mptcp_established_options_fastclose(sk, &opt_size, remaining, opts) ||
|
|
mptcp_established_options_mp_fail(sk, &opt_size, remaining, opts)) {
|
|
*size += opt_size;
|
|
remaining -= opt_size;
|
|
}
|
|
/* MP_RST can be used with MP_FASTCLOSE and MP_FAIL if there is room */
|
|
if (mptcp_established_options_rst(sk, skb, &opt_size, remaining, opts)) {
|
|
*size += opt_size;
|
|
remaining -= opt_size;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
snd_data_fin = mptcp_data_fin_enabled(msk);
|
|
if (mptcp_established_options_mp(sk, skb, snd_data_fin, &opt_size, remaining, opts))
|
|
ret = true;
|
|
else if (mptcp_established_options_dss(sk, skb, snd_data_fin, &opt_size, remaining, opts)) {
|
|
unsigned int mp_fail_size;
|
|
|
|
ret = true;
|
|
if (mptcp_established_options_mp_fail(sk, &mp_fail_size,
|
|
remaining - opt_size, opts)) {
|
|
*size += opt_size + mp_fail_size;
|
|
remaining -= opt_size - mp_fail_size;
|
|
return true;
|
|
}
|
|
}
|
|
|
|
/* we reserved enough space for the above options, and exceeding the
|
|
* TCP option space would be fatal
|
|
*/
|
|
if (WARN_ON_ONCE(opt_size > remaining))
|
|
return false;
|
|
|
|
*size += opt_size;
|
|
remaining -= opt_size;
|
|
if (mptcp_established_options_add_addr(sk, skb, &opt_size, remaining, opts)) {
|
|
*size += opt_size;
|
|
remaining -= opt_size;
|
|
ret = true;
|
|
} else if (mptcp_established_options_rm_addr(sk, &opt_size, remaining, opts)) {
|
|
*size += opt_size;
|
|
remaining -= opt_size;
|
|
ret = true;
|
|
}
|
|
|
|
if (mptcp_established_options_mp_prio(sk, &opt_size, remaining, opts)) {
|
|
*size += opt_size;
|
|
remaining -= opt_size;
|
|
ret = true;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
|
|
struct mptcp_out_options *opts)
|
|
{
|
|
struct mptcp_subflow_request_sock *subflow_req = mptcp_subflow_rsk(req);
|
|
|
|
if (subflow_req->mp_capable) {
|
|
opts->suboptions = OPTION_MPTCP_MPC_SYNACK;
|
|
opts->sndr_key = subflow_req->local_key;
|
|
opts->csum_reqd = subflow_req->csum_reqd;
|
|
opts->allow_join_id0 = subflow_req->allow_join_id0;
|
|
*size = TCPOLEN_MPTCP_MPC_SYNACK;
|
|
pr_debug("subflow_req=%p, local_key=%llu",
|
|
subflow_req, subflow_req->local_key);
|
|
return true;
|
|
} else if (subflow_req->mp_join) {
|
|
opts->suboptions = OPTION_MPTCP_MPJ_SYNACK;
|
|
opts->backup = subflow_req->backup;
|
|
opts->join_id = subflow_req->local_id;
|
|
opts->thmac = subflow_req->thmac;
|
|
opts->nonce = subflow_req->local_nonce;
|
|
pr_debug("req=%p, bkup=%u, id=%u, thmac=%llu, nonce=%u",
|
|
subflow_req, opts->backup, opts->join_id,
|
|
opts->thmac, opts->nonce);
|
|
*size = TCPOLEN_MPTCP_MPJ_SYNACK;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
|
|
struct mptcp_subflow_context *subflow,
|
|
struct sk_buff *skb,
|
|
struct mptcp_options_received *mp_opt)
|
|
{
|
|
/* here we can process OoO, in-window pkts, only in-sequence 4th ack
|
|
* will make the subflow fully established
|
|
*/
|
|
if (likely(subflow->fully_established)) {
|
|
/* on passive sockets, check for 3rd ack retransmission
|
|
* note that msk is always set by subflow_syn_recv_sock()
|
|
* for mp_join subflows
|
|
*/
|
|
if (TCP_SKB_CB(skb)->seq == subflow->ssn_offset + 1 &&
|
|
TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq &&
|
|
subflow->mp_join && (mp_opt->suboptions & OPTIONS_MPTCP_MPJ) &&
|
|
READ_ONCE(msk->pm.server_side))
|
|
tcp_send_ack(ssk);
|
|
goto fully_established;
|
|
}
|
|
|
|
/* we must process OoO packets before the first subflow is fully
|
|
* established. OoO packets are instead a protocol violation
|
|
* for MP_JOIN subflows as the peer must not send any data
|
|
* before receiving the forth ack - cfr. RFC 8684 section 3.2.
|
|
*/
|
|
if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) {
|
|
if (subflow->mp_join)
|
|
goto reset;
|
|
return subflow->mp_capable;
|
|
}
|
|
|
|
if (((mp_opt->suboptions & OPTION_MPTCP_DSS) && mp_opt->use_ack) ||
|
|
((mp_opt->suboptions & OPTION_MPTCP_ADD_ADDR) && !mp_opt->echo)) {
|
|
/* subflows are fully established as soon as we get any
|
|
* additional ack, including ADD_ADDR.
|
|
*/
|
|
subflow->fully_established = 1;
|
|
WRITE_ONCE(msk->fully_established, true);
|
|
goto fully_established;
|
|
}
|
|
|
|
/* If the first established packet does not contain MP_CAPABLE + data
|
|
* then fallback to TCP. Fallback scenarios requires a reset for
|
|
* MP_JOIN subflows.
|
|
*/
|
|
if (!(mp_opt->suboptions & OPTIONS_MPTCP_MPC)) {
|
|
if (subflow->mp_join)
|
|
goto reset;
|
|
subflow->mp_capable = 0;
|
|
pr_fallback(msk);
|
|
__mptcp_do_fallback(msk);
|
|
return false;
|
|
}
|
|
|
|
if (mp_opt->deny_join_id0)
|
|
WRITE_ONCE(msk->pm.remote_deny_join_id0, true);
|
|
|
|
if (unlikely(!READ_ONCE(msk->pm.server_side)))
|
|
pr_warn_once("bogus mpc option on established client sk");
|
|
mptcp_subflow_fully_established(subflow, mp_opt);
|
|
|
|
fully_established:
|
|
/* if the subflow is not already linked into the conn_list, we can't
|
|
* notify the PM: this subflow is still on the listener queue
|
|
* and the PM possibly acquiring the subflow lock could race with
|
|
* the listener close
|
|
*/
|
|
if (likely(subflow->pm_notified) || list_empty(&subflow->node))
|
|
return true;
|
|
|
|
subflow->pm_notified = 1;
|
|
if (subflow->mp_join) {
|
|
clear_3rdack_retransmission(ssk);
|
|
mptcp_pm_subflow_established(msk);
|
|
} else {
|
|
mptcp_pm_fully_established(msk, ssk, GFP_ATOMIC);
|
|
}
|
|
return true;
|
|
|
|
reset:
|
|
mptcp_subflow_reset(ssk);
|
|
return false;
|
|
}
|
|
|
|
u64 __mptcp_expand_seq(u64 old_seq, u64 cur_seq)
|
|
{
|
|
u32 old_seq32, cur_seq32;
|
|
|
|
old_seq32 = (u32)old_seq;
|
|
cur_seq32 = (u32)cur_seq;
|
|
cur_seq = (old_seq & GENMASK_ULL(63, 32)) + cur_seq32;
|
|
if (unlikely(cur_seq32 < old_seq32 && before(old_seq32, cur_seq32)))
|
|
return cur_seq + (1LL << 32);
|
|
|
|
/* reverse wrap could happen, too */
|
|
if (unlikely(cur_seq32 > old_seq32 && after(old_seq32, cur_seq32)))
|
|
return cur_seq - (1LL << 32);
|
|
return cur_seq;
|
|
}
|
|
|
|
static void ack_update_msk(struct mptcp_sock *msk,
|
|
struct sock *ssk,
|
|
struct mptcp_options_received *mp_opt)
|
|
{
|
|
u64 new_wnd_end, new_snd_una, snd_nxt = READ_ONCE(msk->snd_nxt);
|
|
struct sock *sk = (struct sock *)msk;
|
|
u64 old_snd_una;
|
|
|
|
mptcp_data_lock(sk);
|
|
|
|
/* avoid ack expansion on update conflict, to reduce the risk of
|
|
* wrongly expanding to a future ack sequence number, which is way
|
|
* more dangerous than missing an ack
|
|
*/
|
|
old_snd_una = msk->snd_una;
|
|
new_snd_una = mptcp_expand_seq(old_snd_una, mp_opt->data_ack, mp_opt->ack64);
|
|
|
|
/* ACK for data not even sent yet? Ignore.*/
|
|
if (unlikely(after64(new_snd_una, snd_nxt)))
|
|
new_snd_una = old_snd_una;
|
|
|
|
new_wnd_end = new_snd_una + tcp_sk(ssk)->snd_wnd;
|
|
|
|
if (after64(new_wnd_end, msk->wnd_end))
|
|
msk->wnd_end = new_wnd_end;
|
|
|
|
/* this assumes mptcp_incoming_options() is invoked after tcp_ack() */
|
|
if (after64(msk->wnd_end, READ_ONCE(msk->snd_nxt)))
|
|
__mptcp_check_push(sk, ssk);
|
|
|
|
if (after64(new_snd_una, old_snd_una)) {
|
|
msk->snd_una = new_snd_una;
|
|
__mptcp_data_acked(sk);
|
|
}
|
|
mptcp_data_unlock(sk);
|
|
|
|
trace_ack_update_msk(mp_opt->data_ack,
|
|
old_snd_una, new_snd_una,
|
|
new_wnd_end, msk->wnd_end);
|
|
}
|
|
|
|
bool mptcp_update_rcv_data_fin(struct mptcp_sock *msk, u64 data_fin_seq, bool use_64bit)
|
|
{
|
|
/* Skip if DATA_FIN was already received.
|
|
* If updating simultaneously with the recvmsg loop, values
|
|
* should match. If they mismatch, the peer is misbehaving and
|
|
* we will prefer the most recent information.
|
|
*/
|
|
if (READ_ONCE(msk->rcv_data_fin))
|
|
return false;
|
|
|
|
WRITE_ONCE(msk->rcv_data_fin_seq,
|
|
mptcp_expand_seq(READ_ONCE(msk->ack_seq), data_fin_seq, use_64bit));
|
|
WRITE_ONCE(msk->rcv_data_fin, 1);
|
|
|
|
return true;
|
|
}
|
|
|
|
static bool add_addr_hmac_valid(struct mptcp_sock *msk,
|
|
struct mptcp_options_received *mp_opt)
|
|
{
|
|
u64 hmac = 0;
|
|
|
|
if (mp_opt->echo)
|
|
return true;
|
|
|
|
hmac = add_addr_generate_hmac(msk->remote_key,
|
|
msk->local_key,
|
|
&mp_opt->addr);
|
|
|
|
pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n",
|
|
msk, (unsigned long long)hmac,
|
|
(unsigned long long)mp_opt->ahmac);
|
|
|
|
return hmac == mp_opt->ahmac;
|
|
}
|
|
|
|
/* Return false if a subflow has been reset, else return true */
|
|
bool mptcp_incoming_options(struct sock *sk, struct sk_buff *skb)
|
|
{
|
|
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
|
|
struct mptcp_sock *msk = mptcp_sk(subflow->conn);
|
|
struct mptcp_options_received mp_opt;
|
|
struct mptcp_ext *mpext;
|
|
|
|
if (__mptcp_check_fallback(msk)) {
|
|
/* Keep it simple and unconditionally trigger send data cleanup and
|
|
* pending queue spooling. We will need to acquire the data lock
|
|
* for more accurate checks, and once the lock is acquired, such
|
|
* helpers are cheap.
|
|
*/
|
|
mptcp_data_lock(subflow->conn);
|
|
if (sk_stream_memory_free(sk))
|
|
__mptcp_check_push(subflow->conn, sk);
|
|
__mptcp_data_acked(subflow->conn);
|
|
mptcp_data_unlock(subflow->conn);
|
|
return true;
|
|
}
|
|
|
|
mptcp_get_options(sk, skb, &mp_opt);
|
|
|
|
/* The subflow can be in close state only if check_fully_established()
|
|
* just sent a reset. If so, tell the caller to ignore the current packet.
|
|
*/
|
|
if (!check_fully_established(msk, sk, subflow, skb, &mp_opt))
|
|
return sk->sk_state != TCP_CLOSE;
|
|
|
|
if (unlikely(mp_opt.suboptions != OPTION_MPTCP_DSS)) {
|
|
if ((mp_opt.suboptions & OPTION_MPTCP_FASTCLOSE) &&
|
|
msk->local_key == mp_opt.rcvr_key) {
|
|
WRITE_ONCE(msk->rcv_fastclose, true);
|
|
mptcp_schedule_work((struct sock *)msk);
|
|
}
|
|
|
|
if ((mp_opt.suboptions & OPTION_MPTCP_ADD_ADDR) &&
|
|
add_addr_hmac_valid(msk, &mp_opt)) {
|
|
if (!mp_opt.echo) {
|
|
mptcp_pm_add_addr_received(msk, &mp_opt.addr);
|
|
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR);
|
|
} else {
|
|
mptcp_pm_add_addr_echoed(msk, &mp_opt.addr);
|
|
mptcp_pm_del_add_timer(msk, &mp_opt.addr, true);
|
|
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD);
|
|
}
|
|
|
|
if (mp_opt.addr.port)
|
|
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_PORTADD);
|
|
}
|
|
|
|
if (mp_opt.suboptions & OPTION_MPTCP_RM_ADDR)
|
|
mptcp_pm_rm_addr_received(msk, &mp_opt.rm_list);
|
|
|
|
if (mp_opt.suboptions & OPTION_MPTCP_PRIO) {
|
|
mptcp_pm_mp_prio_received(sk, mp_opt.backup);
|
|
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPPRIORX);
|
|
}
|
|
|
|
if (mp_opt.suboptions & OPTION_MPTCP_FAIL) {
|
|
mptcp_pm_mp_fail_received(sk, mp_opt.fail_seq);
|
|
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFAILRX);
|
|
}
|
|
|
|
if (mp_opt.suboptions & OPTION_MPTCP_RST) {
|
|
subflow->reset_seen = 1;
|
|
subflow->reset_reason = mp_opt.reset_reason;
|
|
subflow->reset_transient = mp_opt.reset_transient;
|
|
}
|
|
|
|
if (!(mp_opt.suboptions & OPTION_MPTCP_DSS))
|
|
return true;
|
|
}
|
|
|
|
/* we can't wait for recvmsg() to update the ack_seq, otherwise
|
|
* monodirectional flows will stuck
|
|
*/
|
|
if (mp_opt.use_ack)
|
|
ack_update_msk(msk, sk, &mp_opt);
|
|
|
|
/* Zero-data-length packets are dropped by the caller and not
|
|
* propagated to the MPTCP layer, so the skb extension does not
|
|
* need to be allocated or populated. DATA_FIN information, if
|
|
* present, needs to be updated here before the skb is freed.
|
|
*/
|
|
if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
|
|
if (mp_opt.data_fin && mp_opt.data_len == 1 &&
|
|
mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) &&
|
|
schedule_work(&msk->work))
|
|
sock_hold(subflow->conn);
|
|
|
|
return true;
|
|
}
|
|
|
|
mpext = skb_ext_add(skb, SKB_EXT_MPTCP);
|
|
if (!mpext)
|
|
return true;
|
|
|
|
memset(mpext, 0, sizeof(*mpext));
|
|
|
|
if (likely(mp_opt.use_map)) {
|
|
if (mp_opt.mpc_map) {
|
|
/* this is an MP_CAPABLE carrying MPTCP data
|
|
* we know this map the first chunk of data
|
|
*/
|
|
mptcp_crypto_key_sha(subflow->remote_key, NULL,
|
|
&mpext->data_seq);
|
|
mpext->data_seq++;
|
|
mpext->subflow_seq = 1;
|
|
mpext->dsn64 = 1;
|
|
mpext->mpc_map = 1;
|
|
mpext->data_fin = 0;
|
|
} else {
|
|
mpext->data_seq = mp_opt.data_seq;
|
|
mpext->subflow_seq = mp_opt.subflow_seq;
|
|
mpext->dsn64 = mp_opt.dsn64;
|
|
mpext->data_fin = mp_opt.data_fin;
|
|
}
|
|
mpext->data_len = mp_opt.data_len;
|
|
mpext->use_map = 1;
|
|
mpext->csum_reqd = !!(mp_opt.suboptions & OPTION_MPTCP_CSUMREQD);
|
|
|
|
if (mpext->csum_reqd)
|
|
mpext->csum = mp_opt.csum;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
static void mptcp_set_rwin(const struct tcp_sock *tp)
|
|
{
|
|
const struct sock *ssk = (const struct sock *)tp;
|
|
const struct mptcp_subflow_context *subflow;
|
|
struct mptcp_sock *msk;
|
|
u64 ack_seq;
|
|
|
|
subflow = mptcp_subflow_ctx(ssk);
|
|
msk = mptcp_sk(subflow->conn);
|
|
|
|
ack_seq = READ_ONCE(msk->ack_seq) + tp->rcv_wnd;
|
|
|
|
if (after64(ack_seq, READ_ONCE(msk->rcv_wnd_sent)))
|
|
WRITE_ONCE(msk->rcv_wnd_sent, ack_seq);
|
|
}
|
|
|
|
u16 __mptcp_make_csum(u64 data_seq, u32 subflow_seq, u16 data_len, __wsum sum)
|
|
{
|
|
struct csum_pseudo_header header;
|
|
__wsum csum;
|
|
|
|
/* cfr RFC 8684 3.3.1.:
|
|
* the data sequence number used in the pseudo-header is
|
|
* always the 64-bit value, irrespective of what length is used in the
|
|
* DSS option itself.
|
|
*/
|
|
header.data_seq = cpu_to_be64(data_seq);
|
|
header.subflow_seq = htonl(subflow_seq);
|
|
header.data_len = htons(data_len);
|
|
header.csum = 0;
|
|
|
|
csum = csum_partial(&header, sizeof(header), sum);
|
|
return (__force u16)csum_fold(csum);
|
|
}
|
|
|
|
static u16 mptcp_make_csum(const struct mptcp_ext *mpext)
|
|
{
|
|
return __mptcp_make_csum(mpext->data_seq, mpext->subflow_seq, mpext->data_len,
|
|
~csum_unfold(mpext->csum));
|
|
}
|
|
|
|
void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
|
|
struct mptcp_out_options *opts)
|
|
{
|
|
if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
|
|
const struct sock *ssk = (const struct sock *)tp;
|
|
struct mptcp_subflow_context *subflow;
|
|
|
|
subflow = mptcp_subflow_ctx(ssk);
|
|
subflow->send_mp_fail = 0;
|
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,
|
|
TCPOLEN_MPTCP_FAIL,
|
|
0, 0);
|
|
put_unaligned_be64(opts->fail_seq, ptr);
|
|
ptr += 2;
|
|
}
|
|
|
|
/* DSS, MPC, MPJ, ADD_ADDR, FASTCLOSE and RST are mutually exclusive,
|
|
* see mptcp_established_options*()
|
|
*/
|
|
if (likely(OPTION_MPTCP_DSS & opts->suboptions)) {
|
|
struct mptcp_ext *mpext = &opts->ext_copy;
|
|
u8 len = TCPOLEN_MPTCP_DSS_BASE;
|
|
u8 flags = 0;
|
|
|
|
if (mpext->use_ack) {
|
|
flags = MPTCP_DSS_HAS_ACK;
|
|
if (mpext->ack64) {
|
|
len += TCPOLEN_MPTCP_DSS_ACK64;
|
|
flags |= MPTCP_DSS_ACK64;
|
|
} else {
|
|
len += TCPOLEN_MPTCP_DSS_ACK32;
|
|
}
|
|
}
|
|
|
|
if (mpext->use_map) {
|
|
len += TCPOLEN_MPTCP_DSS_MAP64;
|
|
|
|
/* Use only 64-bit mapping flags for now, add
|
|
* support for optional 32-bit mappings later.
|
|
*/
|
|
flags |= MPTCP_DSS_HAS_MAP | MPTCP_DSS_DSN64;
|
|
if (mpext->data_fin)
|
|
flags |= MPTCP_DSS_DATA_FIN;
|
|
|
|
if (opts->csum_reqd)
|
|
len += TCPOLEN_MPTCP_DSS_CHECKSUM;
|
|
}
|
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_DSS, len, 0, flags);
|
|
|
|
if (mpext->use_ack) {
|
|
if (mpext->ack64) {
|
|
put_unaligned_be64(mpext->data_ack, ptr);
|
|
ptr += 2;
|
|
} else {
|
|
put_unaligned_be32(mpext->data_ack32, ptr);
|
|
ptr += 1;
|
|
}
|
|
}
|
|
|
|
if (mpext->use_map) {
|
|
put_unaligned_be64(mpext->data_seq, ptr);
|
|
ptr += 2;
|
|
put_unaligned_be32(mpext->subflow_seq, ptr);
|
|
ptr += 1;
|
|
if (opts->csum_reqd) {
|
|
put_unaligned_be32(mpext->data_len << 16 |
|
|
mptcp_make_csum(mpext), ptr);
|
|
} else {
|
|
put_unaligned_be32(mpext->data_len << 16 |
|
|
TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
|
|
}
|
|
ptr += 1;
|
|
}
|
|
} else if (OPTIONS_MPTCP_MPC & opts->suboptions) {
|
|
u8 len, flag = MPTCP_CAP_HMAC_SHA256;
|
|
|
|
if (OPTION_MPTCP_MPC_SYN & opts->suboptions) {
|
|
len = TCPOLEN_MPTCP_MPC_SYN;
|
|
} else if (OPTION_MPTCP_MPC_SYNACK & opts->suboptions) {
|
|
len = TCPOLEN_MPTCP_MPC_SYNACK;
|
|
} else if (opts->data_len) {
|
|
len = TCPOLEN_MPTCP_MPC_ACK_DATA;
|
|
if (opts->csum_reqd)
|
|
len += TCPOLEN_MPTCP_DSS_CHECKSUM;
|
|
} else {
|
|
len = TCPOLEN_MPTCP_MPC_ACK;
|
|
}
|
|
|
|
if (opts->csum_reqd)
|
|
flag |= MPTCP_CAP_CHECKSUM_REQD;
|
|
|
|
if (!opts->allow_join_id0)
|
|
flag |= MPTCP_CAP_DENY_JOIN_ID0;
|
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len,
|
|
MPTCP_SUPPORTED_VERSION,
|
|
flag);
|
|
|
|
if (!((OPTION_MPTCP_MPC_SYNACK | OPTION_MPTCP_MPC_ACK) &
|
|
opts->suboptions))
|
|
goto mp_capable_done;
|
|
|
|
put_unaligned_be64(opts->sndr_key, ptr);
|
|
ptr += 2;
|
|
if (!((OPTION_MPTCP_MPC_ACK) & opts->suboptions))
|
|
goto mp_capable_done;
|
|
|
|
put_unaligned_be64(opts->rcvr_key, ptr);
|
|
ptr += 2;
|
|
if (!opts->data_len)
|
|
goto mp_capable_done;
|
|
|
|
if (opts->csum_reqd) {
|
|
put_unaligned_be32(opts->data_len << 16 |
|
|
__mptcp_make_csum(opts->data_seq,
|
|
opts->subflow_seq,
|
|
opts->data_len,
|
|
~csum_unfold(opts->csum)), ptr);
|
|
} else {
|
|
put_unaligned_be32(opts->data_len << 16 |
|
|
TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
|
|
}
|
|
ptr += 1;
|
|
|
|
/* MPC is additionally mutually exclusive with MP_PRIO */
|
|
goto mp_capable_done;
|
|
} else if (OPTIONS_MPTCP_MPJ & opts->suboptions) {
|
|
if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
|
|
*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
|
|
TCPOLEN_MPTCP_MPJ_SYN,
|
|
opts->backup, opts->join_id);
|
|
put_unaligned_be32(opts->token, ptr);
|
|
ptr += 1;
|
|
put_unaligned_be32(opts->nonce, ptr);
|
|
ptr += 1;
|
|
} else if (OPTION_MPTCP_MPJ_SYNACK & opts->suboptions) {
|
|
*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
|
|
TCPOLEN_MPTCP_MPJ_SYNACK,
|
|
opts->backup, opts->join_id);
|
|
put_unaligned_be64(opts->thmac, ptr);
|
|
ptr += 2;
|
|
put_unaligned_be32(opts->nonce, ptr);
|
|
ptr += 1;
|
|
} else {
|
|
*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
|
|
TCPOLEN_MPTCP_MPJ_ACK, 0, 0);
|
|
memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN);
|
|
ptr += 5;
|
|
}
|
|
} else if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
|
|
u8 len = TCPOLEN_MPTCP_ADD_ADDR_BASE;
|
|
u8 echo = MPTCP_ADDR_ECHO;
|
|
|
|
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
|
|
if (opts->addr.family == AF_INET6)
|
|
len = TCPOLEN_MPTCP_ADD_ADDR6_BASE;
|
|
#endif
|
|
|
|
if (opts->addr.port)
|
|
len += TCPOLEN_MPTCP_PORT_LEN;
|
|
|
|
if (opts->ahmac) {
|
|
len += sizeof(opts->ahmac);
|
|
echo = 0;
|
|
}
|
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
|
|
len, echo, opts->addr.id);
|
|
if (opts->addr.family == AF_INET) {
|
|
memcpy((u8 *)ptr, (u8 *)&opts->addr.addr.s_addr, 4);
|
|
ptr += 1;
|
|
}
|
|
#if IS_ENABLED(CONFIG_MPTCP_IPV6)
|
|
else if (opts->addr.family == AF_INET6) {
|
|
memcpy((u8 *)ptr, opts->addr.addr6.s6_addr, 16);
|
|
ptr += 4;
|
|
}
|
|
#endif
|
|
|
|
if (!opts->addr.port) {
|
|
if (opts->ahmac) {
|
|
put_unaligned_be64(opts->ahmac, ptr);
|
|
ptr += 2;
|
|
}
|
|
} else {
|
|
u16 port = ntohs(opts->addr.port);
|
|
|
|
if (opts->ahmac) {
|
|
u8 *bptr = (u8 *)ptr;
|
|
|
|
put_unaligned_be16(port, bptr);
|
|
bptr += 2;
|
|
put_unaligned_be64(opts->ahmac, bptr);
|
|
bptr += 8;
|
|
put_unaligned_be16(TCPOPT_NOP << 8 |
|
|
TCPOPT_NOP, bptr);
|
|
|
|
ptr += 3;
|
|
} else {
|
|
put_unaligned_be32(port << 16 |
|
|
TCPOPT_NOP << 8 |
|
|
TCPOPT_NOP, ptr);
|
|
ptr += 1;
|
|
}
|
|
}
|
|
} else if (unlikely(OPTION_MPTCP_FASTCLOSE & opts->suboptions)) {
|
|
/* FASTCLOSE is mutually exclusive with others except RST */
|
|
*ptr++ = mptcp_option(MPTCPOPT_MP_FASTCLOSE,
|
|
TCPOLEN_MPTCP_FASTCLOSE,
|
|
0, 0);
|
|
put_unaligned_be64(opts->rcvr_key, ptr);
|
|
ptr += 2;
|
|
|
|
if (OPTION_MPTCP_RST & opts->suboptions)
|
|
goto mp_rst;
|
|
return;
|
|
} else if (unlikely(OPTION_MPTCP_RST & opts->suboptions)) {
|
|
mp_rst:
|
|
*ptr++ = mptcp_option(MPTCPOPT_RST,
|
|
TCPOLEN_MPTCP_RST,
|
|
opts->reset_transient,
|
|
opts->reset_reason);
|
|
return;
|
|
}
|
|
|
|
if (OPTION_MPTCP_PRIO & opts->suboptions) {
|
|
const struct sock *ssk = (const struct sock *)tp;
|
|
struct mptcp_subflow_context *subflow;
|
|
|
|
subflow = mptcp_subflow_ctx(ssk);
|
|
subflow->send_mp_prio = 0;
|
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_MP_PRIO,
|
|
TCPOLEN_MPTCP_PRIO,
|
|
opts->backup, TCPOPT_NOP);
|
|
}
|
|
|
|
mp_capable_done:
|
|
if (OPTION_MPTCP_RM_ADDR & opts->suboptions) {
|
|
u8 i = 1;
|
|
|
|
*ptr++ = mptcp_option(MPTCPOPT_RM_ADDR,
|
|
TCPOLEN_MPTCP_RM_ADDR_BASE + opts->rm_list.nr,
|
|
0, opts->rm_list.ids[0]);
|
|
|
|
while (i < opts->rm_list.nr) {
|
|
u8 id1, id2, id3, id4;
|
|
|
|
id1 = opts->rm_list.ids[i];
|
|
id2 = i + 1 < opts->rm_list.nr ? opts->rm_list.ids[i + 1] : TCPOPT_NOP;
|
|
id3 = i + 2 < opts->rm_list.nr ? opts->rm_list.ids[i + 2] : TCPOPT_NOP;
|
|
id4 = i + 3 < opts->rm_list.nr ? opts->rm_list.ids[i + 3] : TCPOPT_NOP;
|
|
put_unaligned_be32(id1 << 24 | id2 << 16 | id3 << 8 | id4, ptr);
|
|
ptr += 1;
|
|
i += 4;
|
|
}
|
|
}
|
|
|
|
if (tp)
|
|
mptcp_set_rwin(tp);
|
|
}
|
|
|
|
__be32 mptcp_get_reset_option(const struct sk_buff *skb)
|
|
{
|
|
const struct mptcp_ext *ext = mptcp_get_ext(skb);
|
|
u8 flags, reason;
|
|
|
|
if (ext) {
|
|
flags = ext->reset_transient;
|
|
reason = ext->reset_reason;
|
|
|
|
return mptcp_option(MPTCPOPT_RST, TCPOLEN_MPTCP_RST,
|
|
flags, reason);
|
|
}
|
|
|
|
return htonl(0u);
|
|
}
|
|
EXPORT_SYMBOL_GPL(mptcp_get_reset_option);
|