diff options
Diffstat (limited to 'net/mptcp/options.c')
| -rw-r--r-- | net/mptcp/options.c | 155 |
1 files changed, 151 insertions, 4 deletions
diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 52ff2301b68b..5ea127bc7f01 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -134,13 +134,13 @@ void mptcp_rcv_synsent(struct sock *sk) } } -bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, - unsigned int *size, unsigned int remaining, - struct mptcp_out_options *opts) +static bool mptcp_established_options_mp(struct sock *sk, unsigned int *size, + unsigned int remaining, + struct mptcp_out_options *opts) { struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); - if (subflow->mp_capable && !subflow->fourth_ack) { + if (!subflow->fourth_ack) { opts->suboptions = OPTION_MPTCP_MPC_ACK; opts->sndr_key = subflow->local_key; opts->rcvr_key = subflow->remote_key; @@ -153,6 +153,112 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb, return false; } +static void mptcp_write_data_fin(struct mptcp_subflow_context *subflow, + struct mptcp_ext *ext) +{ + ext->data_fin = 1; + + if (!ext->use_map) { + /* RFC6824 requires a DSS mapping with specific values + * if DATA_FIN is set but no data payload is mapped + */ + ext->use_map = 1; + ext->dsn64 = 1; + ext->data_seq = mptcp_sk(subflow->conn)->write_seq; + ext->subflow_seq = 0; + ext->data_len = 1; + } else { + /* If there's an existing DSS mapping, DATA_FIN consumes + * 1 additional byte of mapping space. + */ + 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); + unsigned int dss_size = 0; + struct mptcp_ext *mpext; + struct mptcp_sock *msk; + unsigned int ack_size; + u8 tcp_fin; + + if (skb) { + mpext = mptcp_get_ext(skb); + tcp_fin = TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN; + } else { + mpext = NULL; + tcp_fin = 0; + } + + if (!skb || (mpext && mpext->use_map) || tcp_fin) { + 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 && tcp_fin && + subflow->conn->sk_state != TCP_ESTABLISHED) + mptcp_write_data_fin(subflow, &opts->ext_copy); + } + + ack_size = TCPOLEN_MPTCP_DSS_ACK64; + + /* 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; + + msk = mptcp_sk(mptcp_subflow_ctx(sk)->conn); + if (msk) { + opts->ext_copy.data_ack = msk->ack_seq; + } else { + mptcp_crypto_key_sha(mptcp_subflow_ctx(sk)->remote_key, + NULL, &opts->ext_copy.data_ack); + opts->ext_copy.data_ack++; + } + + opts->ext_copy.ack64 = 1; + opts->ext_copy.use_ack = 1; + + *size = ALIGN(dss_size, 4); + 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; + + if (mptcp_established_options_mp(sk, &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; + + return ret; +} + bool mptcp_synack_options(const struct request_sock *req, unsigned int *size, struct mptcp_out_options *opts) { @@ -194,4 +300,45 @@ void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts) ptr += 2; } } + + 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) { + len += TCPOLEN_MPTCP_DSS_ACK64; + flags = MPTCP_DSS_HAS_ACK | MPTCP_DSS_ACK64; + } + + 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++ = htonl((TCPOPT_MPTCP << 24) | + (len << 16) | + (MPTCPOPT_DSS << 12) | + (flags)); + + if (mpext->use_ack) { + put_unaligned_be64(mpext->data_ack, ptr); + ptr += 2; + } + + 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); + } + } } |