| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Peter Krystad | 2231 | 28.45% | 9 | 4.81% |
| Paolo Abeni | 1673 | 21.34% | 53 | 28.34% |
| Geliang Tang | 1533 | 19.55% | 50 | 26.74% |
| Mat Martineau | 1139 | 14.53% | 12 | 6.42% |
| Christoph Paasch | 463 | 5.90% | 3 | 1.60% |
| Florian Westphal | 428 | 5.46% | 7 | 3.74% |
| Davide Caratti | 92 | 1.17% | 7 | 3.74% |
| Linus Torvalds (pre-git) | 67 | 0.85% | 13 | 6.95% |
| Yonglong Li | 42 | 0.54% | 1 | 0.53% |
| Matthieu Baerts | 39 | 0.50% | 6 | 3.21% |
| Jianguo Wu | 25 | 0.32% | 1 | 0.53% |
| Eric Dumazet | 21 | 0.27% | 4 | 2.14% |
| Dmytro Shytyi | 17 | 0.22% | 1 | 0.53% |
| Arnaldo Carvalho de Melo | 17 | 0.22% | 6 | 3.21% |
| Todd Malsbary | 12 | 0.15% | 2 | 1.07% |
| Hideaki Yoshifuji / 吉藤英明 | 10 | 0.13% | 1 | 0.53% |
| Maxim Mikityanskiy | 7 | 0.09% | 1 | 0.53% |
| Edward Adam Davis | 6 | 0.08% | 1 | 0.53% |
| Ilpo Järvinen | 5 | 0.06% | 2 | 1.07% |
| Kishen Maloor | 4 | 0.05% | 2 | 1.07% |
| Kuniyuki Iwashima | 3 | 0.04% | 1 | 0.53% |
| Dmitry Popov | 3 | 0.04% | 1 | 0.53% |
| Alexey Kuznetsov | 2 | 0.03% | 1 | 0.53% |
| Greg Kroah-Hartman | 1 | 0.01% | 1 | 0.53% |
| Eric Biggers | 1 | 0.01% | 1 | 0.53% |
| Total | 7841 | 187 |
// 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; u16 subopt; 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; subopt = OPTION_MPTCP_MPC_ACK; } else { if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK) { expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK; subopt = OPTION_MPTCP_MPC_SYNACK; } else { expected_opsize = TCPOLEN_MPTCP_MPC_SYN; subopt = OPTION_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 |= subopt; 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->use_ack = 0; 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: if (opsize == TCPOLEN_MPTCP_MPJ_SYN) { mp_opt->suboptions |= OPTION_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->suboptions |= OPTION_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) { mp_opt->suboptions |= OPTION_MPTCP_MPJ_ACK; ptr += 2; memcpy(mp_opt->hmac, ptr, MPTCPOPT_HMAC_LEN); pr_debug("MP_JOIN hmac"); } 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, 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, 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; } 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) { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDRTX); opts->ahmac = add_addr_generate_hmac(READ_ONCE(msk->local_key), READ_ONCE(msk->remote_key), &opts->addr); } else { MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADDTX); } 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]); MPTCP_ADD_STATS(sock_net(sk), MPTCP_MIB_RMADDRTX, opts->rm_list.nr); 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 = READ_ONCE(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, opts)) ret = true; else if (mptcp_established_options_dss(sk, skb, snd_data_fin, &opt_size, 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 check_notify; } /* 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; if (subflow->is_mptfo && mp_opt->suboptions & OPTION_MPTCP_MPC_ACK) goto set_fully_established; return subflow->mp_capable; } if (subflow->remote_key_valid && (((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. */ goto set_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"); set_fully_established: mptcp_data_lock((struct sock *)msk); __mptcp_subflow_fully_established(msk, subflow, mp_opt); mptcp_data_unlock((struct sock *)msk); check_notify: /* 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); } 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 __mptcp_snd_una_update(struct mptcp_sock *msk, u64 new_snd_una) { msk->bytes_acked += new_snd_una - msk->snd_una; WRITE_ONCE(msk->snd_una, new_snd_una); } 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)) WRITE_ONCE(msk->wnd_end, new_wnd_end); /* this assumes mptcp_incoming_options() is invoked after tcp_ack() */ if (after64(msk->wnd_end, snd_nxt)) __mptcp_check_push(sk, ssk); if (after64(new_snd_una, old_snd_una)) { __mptcp_snd_una_update(msk, 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, READ_ONCE(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(READ_ONCE(msk->remote_key), READ_ONCE(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); /* on fallback we just need to ignore the msk-level snd_una, as * this is really plain TCP */ __mptcp_snd_una_update(msk, READ_ONCE(msk->snd_nxt)); __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) && READ_ONCE(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; rcv_wnd_old = rcv_wnd; if (before64(rcv_wnd_new, rcv_wnd_old)) { MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICTUPDATE); goto raise_win; } MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICT); } 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(ssk), 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);
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