Update Linux to v5.10.109
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz
Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/net/mptcp/options.c b/net/mptcp/options.c
new file mode 100644
index 0000000..64afe71
--- /dev/null
+++ b/net/mptcp/options.c
@@ -0,0 +1,1137 @@
+// 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/sha.h>
+#include <net/tcp.h>
+#include <net/mptcp.h>
+#include "protocol.h"
+#include "mib.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;
+
+ 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;
+ }
+ if (opsize != expected_opsize)
+ 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."
+ *
+ * Section 3.3.0:
+ * "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 don't implement DSS checksum - fall back to TCP.
+ */
+ if (flags & MPTCP_CAP_CHECKSUM_REQD)
+ break;
+
+ mp_opt->mp_capable = 1;
+ 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->dss = 1;
+ mp_opt->use_map = 1;
+ mp_opt->mpc_map = 1;
+ mp_opt->data_len = get_unaligned_be16(ptr);
+ ptr += 2;
+ }
+ pr_debug("MP_CAPABLE version=%x, flags=%x, optlen=%d sndr=%llu, rcvr=%llu len=%d",
+ version, flags, opsize, mp_opt->sndr_key,
+ mp_opt->rcvr_key, mp_opt->data_len);
+ break;
+
+ case MPTCPOPT_MP_JOIN:
+ mp_opt->mp_join = 1;
+ 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->mp_join = 0;
+ }
+ 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;
+ }
+
+ /* RFC 6824, Section 3.3:
+ * If a checksum is present, but its use had
+ * not been negotiated in the MP_CAPABLE handshake,
+ * the checksum field MUST be ignored.
+ */
+ if (opsize != expected_opsize &&
+ opsize != expected_opsize + TCPOLEN_MPTCP_DSS_CHECKSUM)
+ break;
+
+ mp_opt->dss = 1;
+
+ 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;
+
+ pr_debug("data_seq=%llu subflow_seq=%u data_len=%u",
+ mp_opt->data_seq, mp_opt->subflow_seq,
+ mp_opt->data_len);
+ }
+
+ 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->family = MPTCP_ADDR_IPVERSION_4;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6 ||
+ opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT)
+ mp_opt->family = MPTCP_ADDR_IPVERSION_6;
+#endif
+ else
+ break;
+ } else {
+ if (opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE ||
+ opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT)
+ mp_opt->family = MPTCP_ADDR_IPVERSION_4;
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE ||
+ opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT)
+ mp_opt->family = MPTCP_ADDR_IPVERSION_6;
+#endif
+ else
+ break;
+ }
+
+ mp_opt->add_addr = 1;
+ mp_opt->addr_id = *ptr++;
+ pr_debug("ADD_ADDR: id=%d, echo=%d", mp_opt->addr_id, mp_opt->echo);
+ if (mp_opt->family == MPTCP_ADDR_IPVERSION_4) {
+ memcpy((u8 *)&mp_opt->addr.s_addr, (u8 *)ptr, 4);
+ ptr += 4;
+ if (opsize == TCPOLEN_MPTCP_ADD_ADDR_PORT ||
+ opsize == TCPOLEN_MPTCP_ADD_ADDR_BASE_PORT) {
+ mp_opt->port = get_unaligned_be16(ptr);
+ ptr += 2;
+ }
+ }
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else {
+ memcpy(mp_opt->addr6.s6_addr, (u8 *)ptr, 16);
+ ptr += 16;
+ if (opsize == TCPOLEN_MPTCP_ADD_ADDR6_PORT ||
+ opsize == TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT) {
+ mp_opt->port = get_unaligned_be16(ptr);
+ ptr += 2;
+ }
+ }
+#endif
+ if (!mp_opt->echo) {
+ mp_opt->ahmac = get_unaligned_be64(ptr);
+ ptr += 8;
+ }
+ break;
+
+ case MPTCPOPT_RM_ADDR:
+ if (opsize != TCPOLEN_MPTCP_RM_ADDR_BASE)
+ break;
+
+ ptr++;
+
+ mp_opt->rm_addr = 1;
+ mp_opt->rm_id = *ptr++;
+ pr_debug("RM_ADDR: id=%d", mp_opt->rm_id);
+ 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->mp_capable = 0;
+ mp_opt->mp_join = 0;
+ mp_opt->add_addr = 0;
+ mp_opt->ahmac = 0;
+ mp_opt->port = 0;
+ mp_opt->rm_addr = 0;
+ mp_opt->dss = 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;
+ *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;
+}
+
+/* MP_JOIN client subflow must wait for 4th ack before sending any data:
+ * TCP can't schedule delack timer before the subflow is fully established.
+ * MPTCP uses the delack timer to do 3rd ack retransmissions
+ */
+static void schedule_3rdack_retransmission(struct sock *sk)
+{
+ struct inet_connection_sock *icsk = inet_csk(sk);
+ struct tcp_sock *tp = tcp_sk(sk);
+ unsigned long timeout;
+
+ /* reschedule with a timeout above RTT, as we must look only for drop */
+ if (tp->srtt_us)
+ timeout = usecs_to_jiffies(tp->srtt_us >> (3 - 1));
+ else
+ timeout = TCP_TIMEOUT_INIT;
+ timeout += jiffies;
+
+ WARN_ON_ONCE(icsk->icsk_ack.pending & ICSK_ACK_TIMER);
+ icsk->icsk_ack.pending |= ICSK_ACK_SCHED | ICSK_ACK_TIMER;
+ icsk->icsk_ack.timeout = timeout;
+ sk_reset_timer(sk, &icsk->icsk_delack_timer, timeout);
+}
+
+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,
+ unsigned int *size,
+ unsigned int remaining,
+ struct mptcp_out_options *opts)
+{
+ struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+ struct mptcp_ext *mpext;
+ unsigned int data_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 */
+ if (subflow->fully_established ||
+ subflow->snd_isn != TCP_SKB_CB(skb)->seq)
+ return false;
+
+ if (subflow->mp_capable) {
+ mpext = mptcp_get_ext(skb);
+ data_len = mpext ? mpext->data_len : 0;
+
+ /* we will check ext_copy.data_len in mptcp_write_options() to
+ * discriminate between TCPOLEN_MPTCP_MPC_ACK_DATA and
+ * TCPOLEN_MPTCP_MPC_ACK
+ */
+ opts->ext_copy.data_len = data_len;
+ opts->suboptions = OPTION_MPTCP_MPC_ACK;
+ opts->sndr_key = subflow->local_key;
+ opts->rcvr_key = subflow->remote_key;
+
+ /* 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)
+ *size = ALIGN(TCPOLEN_MPTCP_MPC_ACK_DATA, 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);
+
+ schedule_3rdack_retransmission(sk);
+ 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,
+ 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;
+ u64 snd_data_fin_enable;
+ struct mptcp_ext *mpext;
+ unsigned int ack_size;
+ bool ret = false;
+
+ mpext = skb ? mptcp_get_ext(skb) : NULL;
+ snd_data_fin_enable = READ_ONCE(msk->snd_data_fin_enable);
+
+ if (!skb || (mpext && mpext->use_map) || snd_data_fin_enable) {
+ unsigned int map_size;
+
+ map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
+
+ remaining -= map_size;
+ dss_size = map_size;
+ if (mpext)
+ opts->ext_copy = *mpext;
+
+ if (skb && snd_data_fin_enable)
+ mptcp_write_data_fin(subflow, skb, &opts->ext_copy);
+ 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;
+ }
+
+ if (READ_ONCE(msk->use_64bit_ack)) {
+ ack_size = TCPOLEN_MPTCP_DSS_ACK64;
+ opts->ext_copy.data_ack = READ_ONCE(msk->ack_seq);
+ opts->ext_copy.ack64 = 1;
+ } else {
+ ack_size = TCPOLEN_MPTCP_DSS_ACK32;
+ opts->ext_copy.data_ack32 = (uint32_t)READ_ONCE(msk->ack_seq);
+ opts->ext_copy.ack64 = 0;
+ }
+ opts->ext_copy.use_ack = 1;
+
+ /* 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, u8 addr_id,
+ struct in_addr *addr)
+{
+ u8 hmac[SHA256_DIGEST_SIZE];
+ u8 msg[7];
+
+ msg[0] = addr_id;
+ memcpy(&msg[1], &addr->s_addr, 4);
+ msg[5] = 0;
+ msg[6] = 0;
+
+ mptcp_crypto_hmac_sha(key1, key2, msg, 7, hmac);
+
+ return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
+}
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+static u64 add_addr6_generate_hmac(u64 key1, u64 key2, u8 addr_id,
+ struct in6_addr *addr)
+{
+ u8 hmac[SHA256_DIGEST_SIZE];
+ u8 msg[19];
+
+ msg[0] = addr_id;
+ memcpy(&msg[1], &addr->s6_addr, 16);
+ msg[17] = 0;
+ msg[18] = 0;
+
+ mptcp_crypto_hmac_sha(key1, key2, msg, 19, hmac);
+
+ return get_unaligned_be64(&hmac[SHA256_DIGEST_SIZE - sizeof(u64)]);
+}
+#endif
+
+static bool mptcp_established_options_add_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_addr_info saddr;
+ bool echo;
+ int len;
+
+ if (!mptcp_pm_should_add_signal(msk) ||
+ !(mptcp_pm_add_addr_signal(msk, remaining, &saddr, &echo)))
+ return false;
+
+ len = mptcp_add_addr_len(saddr.family, echo);
+ if (remaining < len)
+ return false;
+
+ *size = len;
+ opts->addr_id = saddr.id;
+ if (saddr.family == AF_INET) {
+ opts->suboptions |= OPTION_MPTCP_ADD_ADDR;
+ opts->addr = saddr.addr;
+ if (!echo) {
+ opts->ahmac = add_addr_generate_hmac(msk->local_key,
+ msk->remote_key,
+ opts->addr_id,
+ &opts->addr);
+ }
+ }
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (saddr.family == AF_INET6) {
+ opts->suboptions |= OPTION_MPTCP_ADD_ADDR6;
+ opts->addr6 = saddr.addr6;
+ if (!echo) {
+ opts->ahmac = add_addr6_generate_hmac(msk->local_key,
+ msk->remote_key,
+ opts->addr_id,
+ &opts->addr6);
+ }
+ }
+#endif
+ pr_debug("addr_id=%d, ahmac=%llu, echo=%d", opts->addr_id, opts->ahmac, echo);
+
+ 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);
+ u8 rm_id;
+
+ if (!mptcp_pm_should_rm_signal(msk) ||
+ !(mptcp_pm_rm_addr_signal(msk, remaining, &rm_id)))
+ return false;
+
+ if (remaining < TCPOLEN_MPTCP_RM_ADDR_BASE)
+ return false;
+
+ *size = TCPOLEN_MPTCP_RM_ADDR_BASE;
+ opts->suboptions |= OPTION_MPTCP_RM_ADDR;
+ opts->rm_id = rm_id;
+
+ pr_debug("rm_id=%d", opts->rm_id);
+
+ return true;
+}
+
+bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
+ unsigned int *size, unsigned int remaining,
+ struct mptcp_out_options *opts)
+{
+ unsigned int opt_size = 0;
+ bool ret = false;
+
+ opts->suboptions = 0;
+
+ if (unlikely(mptcp_check_fallback(sk)))
+ return false;
+
+ /* prevent adding of any MPTCP related options on reset packet
+ * until we support MP_TCPRST/MP_FASTCLOSE
+ */
+ if (unlikely(skb && TCP_SKB_CB(skb)->tcp_flags & TCPHDR_RST))
+ return false;
+
+ if (mptcp_established_options_mp(sk, skb, &opt_size, remaining, opts))
+ ret = true;
+ else if (mptcp_established_options_dss(sk, skb, &opt_size, remaining,
+ opts))
+ ret = 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, &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;
+ }
+
+ 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;
+ *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->mp_join &&
+ READ_ONCE(msk->pm.server_side))
+ tcp_send_ack(ssk);
+ goto fully_established;
+ }
+
+ /* we must process OoO packets before the first subflow is fully
+ * established. OoO packets are instead a protocol violation
+ * for MP_JOIN subflows as the peer must not send any data
+ * before receiving the forth ack - cfr. RFC 8684 section 3.2.
+ */
+ if (TCP_SKB_CB(skb)->seq != subflow->ssn_offset + 1) {
+ if (subflow->mp_join)
+ goto reset;
+ return subflow->mp_capable;
+ }
+
+ if (mp_opt->dss && mp_opt->use_ack) {
+ /* subflows are fully established as soon as we get any
+ * additional ack.
+ */
+ 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->mp_capable) {
+ if (subflow->mp_join)
+ goto reset;
+ subflow->mp_capable = 0;
+ pr_fallback(msk);
+ __mptcp_do_fallback(msk);
+ return false;
+ }
+
+ 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 (likely(subflow->pm_notified))
+ return true;
+
+ subflow->pm_notified = 1;
+ if (subflow->mp_join) {
+ clear_3rdack_retransmission(ssk);
+ mptcp_pm_subflow_established(msk, subflow);
+ } else {
+ mptcp_pm_fully_established(msk);
+ }
+ return true;
+
+reset:
+ mptcp_subflow_reset(ssk);
+ return false;
+}
+
+static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit)
+{
+ u32 old_ack32, cur_ack32;
+
+ if (use_64bit)
+ return cur_ack;
+
+ old_ack32 = (u32)old_ack;
+ cur_ack32 = (u32)cur_ack;
+ cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32;
+ if (unlikely(before(cur_ack32, old_ack32)))
+ return cur_ack + (1LL << 32);
+ return cur_ack;
+}
+
+static void update_una(struct mptcp_sock *msk,
+ struct mptcp_options_received *mp_opt)
+{
+ u64 new_snd_una, snd_una, old_snd_una = atomic64_read(&msk->snd_una);
+ u64 write_seq = READ_ONCE(msk->write_seq);
+
+ /* 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
+ */
+ new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64);
+
+ /* ACK for data not even sent yet? Ignore. */
+ if (after64(new_snd_una, write_seq))
+ new_snd_una = old_snd_una;
+
+ while (after64(new_snd_una, old_snd_una)) {
+ snd_una = old_snd_una;
+ old_snd_una = atomic64_cmpxchg(&msk->snd_una, snd_una,
+ new_snd_una);
+ if (old_snd_una == snd_una) {
+ mptcp_data_acked((struct sock *)msk);
+ break;
+ }
+ }
+}
+
+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) || !READ_ONCE(msk->first))
+ return false;
+
+ WRITE_ONCE(msk->rcv_data_fin_seq,
+ expand_ack(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;
+
+ if (mp_opt->family == MPTCP_ADDR_IPVERSION_4)
+ hmac = add_addr_generate_hmac(msk->remote_key,
+ msk->local_key,
+ mp_opt->addr_id, &mp_opt->addr);
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else
+ hmac = add_addr6_generate_hmac(msk->remote_key,
+ msk->local_key,
+ mp_opt->addr_id, &mp_opt->addr6);
+#endif
+
+ pr_debug("msk=%p, ahmac=%llu, mp_opt->ahmac=%llu\n",
+ msk, (unsigned long long)hmac,
+ (unsigned long long)mp_opt->ahmac);
+
+ return hmac == mp_opt->ahmac;
+}
+
+void 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))
+ return;
+
+ mptcp_get_options(skb, &mp_opt);
+ if (!check_fully_established(msk, sk, subflow, skb, &mp_opt))
+ return;
+
+ if (mp_opt.add_addr && add_addr_hmac_valid(msk, &mp_opt)) {
+ struct mptcp_addr_info addr;
+
+ addr.port = htons(mp_opt.port);
+ addr.id = mp_opt.addr_id;
+ if (mp_opt.family == MPTCP_ADDR_IPVERSION_4) {
+ addr.family = AF_INET;
+ addr.addr = mp_opt.addr;
+ }
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ else if (mp_opt.family == MPTCP_ADDR_IPVERSION_6) {
+ addr.family = AF_INET6;
+ addr.addr6 = mp_opt.addr6;
+ }
+#endif
+ if (!mp_opt.echo) {
+ mptcp_pm_add_addr_received(msk, &addr);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ADDADDR);
+ } else {
+ mptcp_pm_del_add_timer(msk, &addr);
+ MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_ECHOADD);
+ }
+ mp_opt.add_addr = 0;
+ }
+
+ if (mp_opt.rm_addr) {
+ mptcp_pm_rm_addr_received(msk, mp_opt.rm_id);
+ mp_opt.rm_addr = 0;
+ }
+
+ if (!mp_opt.dss)
+ return;
+
+ /* we can't wait for recvmsg() to update the ack_seq, otherwise
+ * monodirectional flows will stuck
+ */
+ if (mp_opt.use_ack)
+ update_una(msk, &mp_opt);
+
+ /* Zero-data-length packets are dropped by the caller and not
+ * propagated to the MPTCP layer, so the skb extension does not
+ * need to be allocated or populated. DATA_FIN information, if
+ * present, needs to be updated here before the skb is freed.
+ */
+ if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq) {
+ if (mp_opt.data_fin && mp_opt.data_len == 1 &&
+ mptcp_update_rcv_data_fin(msk, mp_opt.data_seq, mp_opt.dsn64) &&
+ schedule_work(&msk->work))
+ sock_hold(subflow->conn);
+
+ return;
+ }
+
+ mpext = skb_ext_add(skb, SKB_EXT_MPTCP);
+ if (!mpext)
+ return;
+
+ memset(mpext, 0, sizeof(*mpext));
+
+ if (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;
+ }
+}
+
+void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)
+{
+ if ((OPTION_MPTCP_MPC_SYN | OPTION_MPTCP_MPC_SYNACK |
+ OPTION_MPTCP_MPC_ACK) & opts->suboptions) {
+ u8 len;
+
+ 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->ext_copy.data_len)
+ len = TCPOLEN_MPTCP_MPC_ACK_DATA;
+ else
+ len = TCPOLEN_MPTCP_MPC_ACK;
+
+ *ptr++ = mptcp_option(MPTCPOPT_MP_CAPABLE, len,
+ MPTCP_SUPPORTED_VERSION,
+ MPTCP_CAP_HMAC_SHA256);
+
+ 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->ext_copy.data_len)
+ goto mp_capable_done;
+
+ put_unaligned_be32(opts->ext_copy.data_len << 16 |
+ TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
+ ptr += 1;
+ }
+
+mp_capable_done:
+ if (OPTION_MPTCP_ADD_ADDR & opts->suboptions) {
+ if (opts->ahmac)
+ *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
+ TCPOLEN_MPTCP_ADD_ADDR, 0,
+ opts->addr_id);
+ else
+ *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
+ TCPOLEN_MPTCP_ADD_ADDR_BASE,
+ MPTCP_ADDR_ECHO,
+ opts->addr_id);
+ memcpy((u8 *)ptr, (u8 *)&opts->addr.s_addr, 4);
+ ptr += 1;
+ if (opts->ahmac) {
+ put_unaligned_be64(opts->ahmac, ptr);
+ ptr += 2;
+ }
+ }
+
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+ if (OPTION_MPTCP_ADD_ADDR6 & opts->suboptions) {
+ if (opts->ahmac)
+ *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
+ TCPOLEN_MPTCP_ADD_ADDR6, 0,
+ opts->addr_id);
+ else
+ *ptr++ = mptcp_option(MPTCPOPT_ADD_ADDR,
+ TCPOLEN_MPTCP_ADD_ADDR6_BASE,
+ MPTCP_ADDR_ECHO,
+ opts->addr_id);
+ memcpy((u8 *)ptr, opts->addr6.s6_addr, 16);
+ ptr += 4;
+ if (opts->ahmac) {
+ put_unaligned_be64(opts->ahmac, ptr);
+ ptr += 2;
+ }
+ }
+#endif
+
+ if (OPTION_MPTCP_RM_ADDR & opts->suboptions) {
+ *ptr++ = mptcp_option(MPTCPOPT_RM_ADDR,
+ TCPOLEN_MPTCP_RM_ADDR_BASE,
+ 0, opts->rm_id);
+ }
+
+ 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;
+ }
+
+ 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;
+ }
+
+ if (OPTION_MPTCP_MPJ_ACK & opts->suboptions) {
+ *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
+ TCPOLEN_MPTCP_MPJ_ACK, 0, 0);
+ memcpy(ptr, opts->hmac, MPTCPOPT_HMAC_LEN);
+ ptr += 5;
+ }
+
+ if (opts->ext_copy.use_ack || opts->ext_copy.use_map) {
+ 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;
+ }
+
+ *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;
+ put_unaligned_be32(mpext->data_len << 16 |
+ TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
+ }
+ }
+}