diff --git a/net/mptcp/options.c b/net/mptcp/options.c index ae69059583a73e..2e2551590ecd02 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -71,11 +71,9 @@ static void mptcp_parse_option(const struct sk_buff *skb, * "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->csum_reqd = 1; mp_opt->mp_capable = 1; if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) { @@ -327,6 +325,8 @@ void mptcp_get_options(const struct sock *sk, const struct sk_buff *skb, struct mptcp_options_received *mp_opt) { + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); + struct mptcp_sock *msk = mptcp_sk(subflow->conn); const struct tcphdr *th = tcp_hdr(skb); const unsigned char *ptr; int length; @@ -342,6 +342,7 @@ void mptcp_get_options(const struct sock *sk, mp_opt->dss = 0; mp_opt->mp_prio = 0; mp_opt->reset = 0; + mp_opt->csum_reqd = READ_ONCE(msk->csum_enabled); length = (th->doff * 4) - sizeof(struct tcphdr); ptr = (const unsigned char *)(th + 1); diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index f0da067301f631..b6e5c09305335d 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2810,6 +2810,8 @@ struct sock *mptcp_sk_clone(const struct sock *sk, msk->token = subflow_req->token; msk->subflow = NULL; WRITE_ONCE(msk->fully_established, false); + if (mp_opt->csum_reqd) + WRITE_ONCE(msk->csum_enabled, true); msk->write_seq = subflow_req->idsn + 1; msk->snd_nxt = msk->write_seq; diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index a7ed0b8eb9bc42..66e5063ac6c939 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -133,6 +133,7 @@ struct mptcp_options_received { rm_addr : 1, mp_prio : 1, echo : 1, + csum_reqd : 1, backup : 1; u32 token; u32 nonce; diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index aa6b307b27c84a..9b82ce635c6e6d 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -405,6 +405,8 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb) goto fallback; } + if (mp_opt.csum_reqd) + WRITE_ONCE(mptcp_sk(parent)->csum_enabled, true); subflow->mp_capable = 1; subflow->can_ack = 1; subflow->remote_key = mp_opt.sndr_key;