| // SPDX-License-Identifier: GPL-2.0 |
| /* Multipath TCP |
| * |
| * Copyright (c) 2017 - 2019, Intel Corporation. |
| */ |
| |
| #define pr_fmt(fmt) "MPTCP: " fmt |
| |
| #include <linux/kernel.h> |
| #include <crypto/sha2.h> |
| #include <net/tcp.h> |
| #include <net/mptcp.h> |
| #include "protocol.h" |
| #include "mib.h" |
| |
| #include <trace/events/mptcp.h> |
| |
| static bool mptcp_cap_flag_sha256(u8 flags) |
| { |
| return (flags & MPTCP_CAP_FLAG_MASK) == MPTCP_CAP_HMAC_SHA256; |
| } |
| |
| static void mptcp_parse_option(const struct sk_buff *skb, |
| const unsigned char *ptr, int opsize, |
| struct mptcp_options_received *mp_opt) |
| { |
| u8 subtype = *ptr >> 4; |
| int expected_opsize; |
| u8 version; |
| u8 flags; |
| u8 i; |
| |
| switch (subtype) { |
| case MPTCPOPT_MP_CAPABLE: |
| /* strict size checking */ |
| if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) { |
| if (skb->len > tcp_hdr(skb)->doff << 2) |
| expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA; |
| else |
| expected_opsize = TCPOLEN_MPTCP_MPC_ACK; |
| } else { |
| if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK) |
| expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK; |
| else |
| expected_opsize = TCPOLEN_MPTCP_MPC_SYN; |
| } |
| |
| /* Cfr RFC 8684 Section 3.3.0: |
| * If a checksum is present but its use had |
| * not been negotiated in the MP_CAPABLE handshake, the receiver MUST |
| * close the subflow with a RST, as it is not behaving as negotiated. |
| * If a checksum is not present when its use has been negotiated, the |
| * receiver MUST close the subflow with a RST, as it is considered |
| * broken |
| * We parse even option with mismatching csum presence, so that |
| * later in subflow_data_ready we can trigger the reset. |
| */ |
| if (opsize != expected_opsize && |
| (expected_opsize != TCPOLEN_MPTCP_MPC_ACK_DATA || |
| opsize != TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM)) |
| break; |
| |
| /* try to be gentle vs future versions on the initial syn */ |
| version = *ptr++ & MPTCP_VERSION_MASK; |
| if (opsize != TCPOLEN_MPTCP_MPC_SYN) { |
| if (version != MPTCP_SUPPORTED_VERSION) |
| break; |
| } else if (version < MPTCP_SUPPORTED_VERSION) { |
| break; |
| } |
| |
| flags = *ptr++; |
| if (!mptcp_cap_flag_sha256(flags) || |
| (flags & MPTCP_CAP_EXTENSIBILITY)) |
| break; |
| |
| /* RFC 6824, Section 3.1: |
| * "For the Checksum Required bit (labeled "A"), if either |
| * host requires the use of checksums, checksums MUST be used. |
| * In other words, the only way for checksums not to be used |
| * is if both hosts in their SYNs set A=0." |
| */ |
| if (flags & MPTCP_CAP_CHECKSUM_REQD) |
| mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
| |
| mp_opt->deny_join_id0 = !!(flags & MPTCP_CAP_DENY_JOIN_ID0); |
| |
| mp_opt->suboptions |= OPTIONS_MPTCP_MPC; |
| if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) { |
| mp_opt->sndr_key = get_unaligned_be64(ptr); |
| ptr += 8; |
| } |
| if (opsize >= TCPOLEN_MPTCP_MPC_ACK) { |
| mp_opt->rcvr_key = get_unaligned_be64(ptr); |
| ptr += 8; |
| } |
| if (opsize >= TCPOLEN_MPTCP_MPC_ACK_DATA) { |
| /* Section 3.1.: |
| * "the data parameters in a MP_CAPABLE are semantically |
| * equivalent to those in a DSS option and can be used |
| * interchangeably." |
| */ |
| mp_opt->suboptions |= OPTION_MPTCP_DSS; |
| mp_opt->use_map = 1; |
| mp_opt->mpc_map = 1; |
| mp_opt->data_len = get_unaligned_be16(ptr); |
| ptr += 2; |
| } |
| if (opsize == TCPOLEN_MPTCP_MPC_ACK_DATA_CSUM) { |
| mp_opt->csum = get_unaligned((__force __sum16 *)ptr); |
| mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
| ptr += 2; |
| } |
| pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d csum=%u", |
| version, flags, opsize, mp_opt->sndr_key, |
| mp_opt->rcvr_key, mp_opt->data_len, mp_opt->csum); |
| break; |
| |
| case MPTCPOPT_MP_JOIN: |
| mp_opt->suboptions |= OPTIONS_MPTCP_MPJ; |
| if (opsize == TCPOLEN_MPTCP_MPJ_SYN) { |
| mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; |
| mp_opt->join_id = *ptr++; |
| mp_opt->token = get_unaligned_be32(ptr); |
| ptr += 4; |
| mp_opt->nonce = get_unaligned_be32(ptr); |
| ptr += 4; |
| pr_debug("MP_JOIN bkup=%u, id=%u, token=%u, nonce=%u", |
| mp_opt->backup, mp_opt->join_id, |
| mp_opt->token, mp_opt->nonce); |
| } else if (opsize == TCPOLEN_MPTCP_MPJ_SYNACK) { |
| mp_opt->backup = *ptr++ & MPTCPOPT_BACKUP; |
| mp_opt->join_id = *ptr++; |
| mp_opt->thmac = get_unaligned_be64(ptr); |
| ptr += 8; |
| mp_opt->nonce = get_unaligned_be32(ptr); |
| ptr += 4; |
| pr_debug("MP_JOIN bkup=%u, id=%u, thmac=%llu, nonce=%u", |
| mp_opt->backup, mp_opt->join_id, |
| mp_opt->thmac, mp_opt->nonce); |
| } else if (opsize == TCPOLEN_MPTCP_MPJ_ACK) { |
| ptr += 2; |
| memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN); |
| pr_debug("MP_JOIN hmac"); |
| } else { |
| mp_opt->suboptions &= ~OPTIONS_MPTCP_MPJ; |
| } |
| break; |
| |
| case MPTCPOPT_DSS: |
| pr_debug("DSS"); |
| ptr++; |
| |
| /* we must clear 'mpc_map' be able to detect MP_CAPABLE |
| * map vs DSS map in mptcp_incoming_options(), and reconstruct |
| * map info accordingly |
| */ |
| mp_opt->mpc_map = 0; |
| flags = (*ptr++) & MPTCP_DSS_FLAG_MASK; |
| mp_opt->data_fin = (flags & MPTCP_DSS_DATA_FIN) != 0; |
| mp_opt->dsn64 = (flags & MPTCP_DSS_DSN64) != 0; |
| mp_opt->use_map = (flags & MPTCP_DSS_HAS_MAP) != 0; |
| mp_opt->ack64 = (flags & MPTCP_DSS_ACK64) != 0; |
| mp_opt->use_ack = (flags & MPTCP_DSS_HAS_ACK); |
| |
| pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d", |
| mp_opt->data_fin, mp_opt->dsn64, |
| mp_opt->use_map, mp_opt->ack64, |
| mp_opt->use_ack); |
| |
| expected_opsize = TCPOLEN_MPTCP_DSS_BASE; |
| |
| if (mp_opt->use_ack) { |
| if (mp_opt->ack64) |
| expected_opsize += TCPOLEN_MPTCP_DSS_ACK64; |
| else |
| expected_opsize += TCPOLEN_MPTCP_DSS_ACK32; |
| } |
| |
| if (mp_opt->use_map) { |
| if (mp_opt->dsn64) |
| expected_opsize += TCPOLEN_MPTCP_DSS_MAP64; |
| else |
| expected_opsize += TCPOLEN_MPTCP_DSS_MAP32; |
| } |
| |
| /* Always parse any csum presence combination, we will enforce |
| * RFC 8684 Section 3.3.0 checks later in subflow_data_ready |
| */ |
| if (opsize != expected_opsize && |
| opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) |
| break; |
| |
| mp_opt->suboptions |= OPTION_MPTCP_DSS; |
| if (mp_opt->use_ack) { |
| if (mp_opt->ack64) { |
| mp_opt->data_ack = get_unaligned_be64(ptr); |
| ptr += 8; |
| } else { |
| mp_opt->data_ack = get_unaligned_be32(ptr); |
| ptr += 4; |
| } |
| |
| pr_debug("data_ack=%llu", mp_opt->data_ack); |
| } |
| |
| if (mp_opt->use_map) { |
| if (mp_opt->dsn64) { |
| mp_opt->data_seq = get_unaligned_be64(ptr); |
| ptr += 8; |
| } else { |
| mp_opt->data_seq = get_unaligned_be32(ptr); |
| ptr += 4; |
| } |
| |
| mp_opt->subflow_seq = get_unaligned_be32(ptr); |
| ptr += 4; |
| |
| mp_opt->data_len = get_unaligned_be16(ptr); |
| ptr += 2; |
| |
| if (opsize == expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM) { |
| mp_opt->suboptions |= OPTION_MPTCP_CSUMREQD; |
| mp_opt->csum = get_unaligned((__force __sum16 *)ptr); |
| ptr += 2; |
| } |
| |
| pr_debug("data_seq=%llu subflow_seq=%u data_len=%u csum=%d:%u", |
| mp_opt->data_seq, mp_opt->subflow_seq, |
| mp_opt->data_len, !!(mp_opt->suboptions & OPTION_MPTCP_CSUMREQD), |
| mp_opt->csum); |
| } |
| |
| break; |
| |
| case MPTCPOPT_ADD_ADDR: |
| mp_opt->echo = (*ptr++) & MPTCP_ADDR_ECHO; |
| if (!mp_opt->echo) { |
| if (opsize == TCPOLEN_MPTCP_ADD_ADDR || |
| opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT) |
| mp_opt->addr.family = AF_INET; |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 || |
| opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT) |
| mp_opt->addr.family = AF_INET6; |
| #endif |
| else |
| break; |
| } else { |
| if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE || |
| opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) |
| mp_opt->addr.family = AF_INET; |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE || |
| opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) |
| mp_opt->addr.family = AF_INET6; |
| #endif |
| else |
| break; |
| } |
| |
| mp_opt->suboptions |= OPTION_MPTCP_ADD_ADDR; |
| mp_opt->addr.id = *ptr++; |
| mp_opt->addr.port = 0; |
| mp_opt->ahmac = 0; |
| if (mp_opt->addr.family == AF_INET) { |
| memcpy((u8 *)&mp_opt->addr.addr.s_addr, (u8 *)ptr, 4); |
| ptr += 4; |
| if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT || |
| opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) { |
| mp_opt->addr.port = htons(get_unaligned_be16(ptr)); |
| ptr += 2; |
| } |
| } |
| #if IS_ENABLED(CONFIG_MPTCP_IPV6) |
| else { |
| memcpy(mp_opt->addr.addr6.s6_addr, (u8 *)ptr, 16); |
| ptr += 16; |
| if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT || |
| opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) { |
| mp_opt->addr.port = htons(get_unaligned_be16(ptr)); |
| ptr += 2; |
| } |
| } |
| #endif |
| if (!mp_opt->echo) { |
| mp_opt->ahmac = get_unaligned_be64(ptr); |
| ptr += 8; |
| } |
| pr_debug("ADD_ADDR%s: id=%d, ahmac=%llu, echo=%d, port=%d", |
| (mp_opt->addr.family == AF_INET6) ? "6" : "", |
| mp_opt->addr.id, mp_opt->ahmac, mp_opt->echo, ntohs(mp_opt->addr.port)); |
| break; |
| |
| case MPTCPOPT_RM_ADDR: |
| if (opsize < TCPOLEN_MPTCP_RM_ADDR_BASE + 1 || |
| opsize > TCPOLEN_MPTCP_RM_ADDR_BASE + MPTCP_RM_IDS_MAX) |
| break; |
| |
| ptr++; |
| |
| mp_opt->suboptions |= OPTION_MPTCP_RM_ADDR; |
| mp_opt->rm_list.nr = opsize - TCPOLEN_MPTCP_RM_ADDR_BASE; |
| for (i = 0; i < mp_opt->rm_list.nr; i++) |
| mp_opt->rm_list.ids[i] = *ptr++; |
| pr_debug("RM_ADDR: rm_list_nr=%d", mp_opt->rm_list.nr); |
| break; |
| |
| case MPTCPOPT_MP_PRIO: |
| if (opsize != TCPOLEN_MPTCP_PRIO) |
| break; |
| |
| mp_opt->suboptions |= OPTION_MPTCP_PRIO; |
| mp_opt->backup = *ptr++ & MPTCP_PRIO_BKUP; |
| pr_debug("MP_PRIO: prio=%d", mp_opt->backup); |
| break; |
| |
| case MPTCPOPT_MP_FASTCLOSE: |
| if (opsize != TCPOLEN_MPTCP_FASTCLOSE) |
| break; |
| |
| ptr += 2; |
| mp_opt->rcvr_key = get_unaligned_be64(ptr); |
| ptr += 8; |
| mp_opt->suboptions |= OPTION_MPTCP_FASTCLOSE; |
| pr_debug("MP_FASTCLOSE: recv_key=%llu", mp_opt->rcvr_key); |
| break; |
| |
| case MPTCPOPT_RST: |
| if (opsize != TCPOLEN_MPTCP_RST) |
| break; |
| |
| if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST)) |
| break; |
| |
| mp_opt->suboptions |= OPTION_MPTCP_RST; |
| flags = *ptr++; |
| mp_opt->reset_transient = flags & MPTCP_RST_TRANSIENT; |
| mp_opt->reset_reason = *ptr; |
| pr_debug("MP_RST: transient=%u reason=%u", |
| mp_opt->reset_transient, mp_opt->reset_reason); |
| break; |
| |
| case MPTCPOPT_MP_FAIL: |
| if (opsize != TCPOLEN_MPTCP_FAIL) |
| break; |
| |
| ptr += 2; |
| mp_opt->suboptions |= OPTION_MPTCP_FAIL; |
| mp_opt->fail_seq = get_unaligned_be64(ptr); |
| pr_debug("MP_FAIL: data_seq=%llu", mp_opt->fail_seq); |
| break; |
| |
| default: |
| break; |
| } |
| } |
| |
| void mptcp_get_options(const struct sk_buff *skb, |
| struct mptcp_options_received *mp_opt) |
| { |
| const struct tcphdr *th = tcp_hdr(skb); |
| const unsigned char *ptr; |
| int length; |
| |
| /* initialize option status */ |
| mp_opt->suboptions = 0; |
| |
| length = (th->doff * 4) - sizeof(struct tcphdr); |
| ptr = (const unsigned char *)(th + 1); |
| |
| while (length > 0) { |
| int opcode = *ptr++; |
| int opsize; |
| |
| switch (opcode) { |
| case TCPOPT_EOL: |
| return; |
| case TCPOPT_NOP: /* Ref: RFC 793 section 3.1 */ |
| length--; |
| continue; |
| default: |
| if (length < 2) |
| return; |
| opsize = *ptr++; |
| if (opsize < 2) /* "silly options" */ |
| return; |
| if (opsize > length) |
| return; /* don't parse partial options */ |
| if (opcode == TCPOPT_MPTCP) |
| mptcp_parse_option(skb, ptr, opsize, mp_opt); |
| ptr += opsize - 2; |
| length -= opsize; |
| } |
| } |
| } |
| |
| bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb, |
| unsigned int *size, struct mptcp_out_options *opts) |
| { |
| struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); |
| |
| /* we will use snd_isn to detect first pkt [re]transmission |
| * in mptcp_established_options_mp() |
| */ |
| subflow->snd_isn = TCP_SKB_CB(skb)->end_seq; |
| if (subflow->request_mptcp) { |
| opts->suboptions = OPTION_MPTCP_MPC_SYN; |
| opts->csum_reqd = mptcp_is_checksum_enabled(sock_net(sk)); |
| opts->allow_join_id0 = mptcp_allow_join_id0(sock_net(sk)); |
| *size = TCPOLEN_MPTCP_MPC_SYN; |
| return true; |
| } else if (subflow->request_join) { |
| pr_debug("remote_token=%u, nonce=%u", subflow->remote_token, |
| subflow->local_nonce); |
| opts->suboptions = OPTION_MPTCP_MPJ_SYN; |
| opts->join_id = subflow->local_id; |
| opts->token = subflow->remote_token; |
| opts->nonce = subflow->local_nonce; |
| opts->backup = subflow->request_bkup; |
| *size = TCPOLEN_MPTCP_MPJ_SYN; |
| return true; |
| } |
| return false; |
| } |
| |
| static void clear_3rdack_retransmission(struct sock *sk) |
| { |
| struct inet_connection_sock *icsk = inet_csk(sk); |
| |
| sk_stop_timer(sk, &icsk->icsk_delack_timer); |
| icsk->icsk_ack.timeout = 0; |
| icsk->icsk_ack.ato = 0; |
| icsk->icsk_ack.pending &= ~(ICSK_ACK_SCHED | ICSK_ACK_TIMER); |
| } |
| |
| static bool mptcp_established_options_mp(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); |
| struct mptcp_ext *mpext; |
| unsigned int data_len; |
| u8 len; |
| |
| /* When skb is not available, we better over-estimate the emitted |
| * options len. A full DSS option (28 bytes) is longer than |
| * TCPOLEN_MPTCP_MPC_ACK_DATA(22) or TCPOLEN_MPTCP_MPJ_ACK(24), so |
| * tell the caller to defer the estimate to |
| * mptcp_established_options_dss(), which will reserve enough space. |
| */ |
| if (!skb) |
| return false; |
| |
| /* MPC/MPJ needed only on 3rd ack packet, DATA_FIN and TCP shutdown take precedence */ |
| if (subflow->fully_established || snd_data_fin_enable || |
| 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; |
| 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, &drop_other_suboptions)) |
| return false; |
| |
| if (drop_other_suboptions) |
| remaining += opt_size; |
| len = mptcp_add_addr_len(opts->addr.family, echo, !!opts->addr.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; |
| MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPRSTTX); |
| |
| 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); |
| MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFASTCLOSETX); |
| 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); |
| MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFAILTX); |
| |
| 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) && !mptcp_check_infinite_map(skb))) |
| 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) && |
| !subflow->request_join) |
| 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(ssk); |
| 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, hmac, 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(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); |
| MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPFASTCLOSERX); |
| } |
| |
| if ((mp_opt.suboptions & OPTION_MPTCP_ADD_ADDR) && |
| add_addr_hmac_valid(msk, &mp_opt)) { |
| if (!mp_opt.echo) { |
| mptcp_pm_add_addr_received(sk, &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; |
| MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_MPRSTRX); |
| } |
| |
| 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)) |
| mptcp_schedule_work((struct sock *)msk); |
| |
| 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(struct tcp_sock *tp, struct tcphdr *th) |
| { |
| const struct sock *ssk = (const struct sock *)tp; |
| struct mptcp_subflow_context *subflow; |
| u64 ack_seq, rcv_wnd_old, rcv_wnd_new; |
| struct mptcp_sock *msk; |
| u32 new_win; |
| u64 win; |
| |
| subflow = mptcp_subflow_ctx(ssk); |
| msk = mptcp_sk(subflow->conn); |
| |
| ack_seq = READ_ONCE(msk->ack_seq); |
| rcv_wnd_new = ack_seq + tp->rcv_wnd; |
| |
| rcv_wnd_old = atomic64_read(&msk->rcv_wnd_sent); |
| if (after64(rcv_wnd_new, rcv_wnd_old)) { |
| u64 rcv_wnd; |
| |
| for (;;) { |
| rcv_wnd = atomic64_cmpxchg(&msk->rcv_wnd_sent, rcv_wnd_old, rcv_wnd_new); |
| |
| if (rcv_wnd == rcv_wnd_old) |
| break; |
| if (before64(rcv_wnd_new, rcv_wnd)) { |
| MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICTUPDATE); |
| goto raise_win; |
| } |
| MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICT); |
| rcv_wnd_old = rcv_wnd; |
| } |
| return; |
| } |
| |
| if (rcv_wnd_new != rcv_wnd_old) { |
| raise_win: |
| win = rcv_wnd_old - ack_seq; |
| tp->rcv_wnd = min_t(u64, win, U32_MAX); |
| new_win = tp->rcv_wnd; |
| |
| /* Make sure we do not exceed the maximum possible |
| * scaled window. |
| */ |
| if (unlikely(th->syn)) |
| new_win = min(new_win, 65535U) << tp->rx_opt.rcv_wscale; |
| if (!tp->rx_opt.rcv_wscale && |
| READ_ONCE(sock_net(ssk)->ipv4.sysctl_tcp_workaround_signed_windows)) |
| new_win = min(new_win, MAX_TCP_WINDOW); |
| else |
| new_win = min(new_win, (65535U << tp->rx_opt.rcv_wscale)); |
| |
| /* RFC1323 scaling applied */ |
| new_win >>= tp->rx_opt.rcv_wscale; |
| th->window = htons(new_win); |
| MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDSHARED); |
| } |
| } |
| |
| __sum16 __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 csum_fold(csum); |
| } |
| |
| static __sum16 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)); |
| } |
| |
| static void put_len_csum(u16 len, __sum16 csum, void *data) |
| { |
| __sum16 *sumptr = data + 2; |
| __be16 *ptr = data; |
| |
| put_unaligned_be16(len, ptr); |
| |
| put_unaligned(csum, sumptr); |
| } |
| |
| void mptcp_write_options(struct tcphdr *th, __be32 *ptr, struct tcp_sock *tp, |
| struct mptcp_out_options *opts) |
| { |
| const struct sock *ssk = (const struct sock *)tp; |
| struct mptcp_subflow_context *subflow; |
| |
| /* Which options can be used together? |
| * |
| * X: mutually exclusive |
| * O: often used together |
| * C: can be used together in some cases |
| * P: could be used together but we prefer not to (optimisations) |
| * |
| * Opt: | MPC | MPJ | DSS | ADD | RM | PRIO | FAIL | FC | |
| * ------|------|------|------|------|------|------|------|------| |
| * MPC |------|------|------|------|------|------|------|------| |
| * MPJ | X |------|------|------|------|------|------|------| |
| * DSS | X | X |------|------|------|------|------|------| |
| * ADD | X | X | P |------|------|------|------|------| |
| * RM | C | C | C | P |------|------|------|------| |
| * PRIO | X | C | C | C | C |------|------|------| |
| * FAIL | X | X | C | X | X | X |------|------| |
| * FC | X | X | X | X | X | X | X |------| |
| * RST | X | X | X | X | X | X | O | O | |
| * ------|------|------|------|------|------|------|------|------| |
| * |
| * The same applies in mptcp_established_options() function. |
| */ |
| 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) { |
| /* data_len == 0 is reserved for the infinite mapping, |
| * the checksum will also be set to 0. |
| */ |
| put_len_csum(mpext->data_len, |
| (mpext->data_len ? mptcp_make_csum(mpext) : 0), |
| ptr); |
| } else { |
| put_unaligned_be32(mpext->data_len << 16 | |
| TCPOPT_NOP << 8 | TCPOPT_NOP, ptr); |
| } |
| ptr += 1; |
| } |
| |
| /* We might need to add MP_FAIL options in rare cases */ |
| if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) |
| goto mp_fail; |
| } 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_len_csum(opts->data_len, |
| __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_FAIL & opts->suboptions)) { |
| mp_fail: |
| /* MP_FAIL is mutually exclusive with others except RST */ |
| 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; |
| |
| 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) { |
| subflow = mptcp_subflow_ctx(ssk); |
| subflow->send_mp_prio = 0; |
| |
| *ptr++ = mptcp_option(MPTCPOPT_MP_PRIO, |
| TCPOLEN_MPTCP_PRIO, |
| opts->backup, TCPOPT_NOP); |
| |
| MPTCP_INC_STATS(sock_net((const struct sock *)tp), |
| MPTCP_MIB_MPPRIOTX); |
| } |
| |
| 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, th); |
| } |
| |
| __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); |