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[v6,mptcp-next,13/22] mptcp: receive checksum for DSS

Message ID 3ba84319faa5ea5d9c8fab44ac525ace19a17069.1620163861.git.pabeni@redhat.com
State Accepted, archived
Commit dcf392ee537c7aaabfcb8a96acfa7e5c6b52fe95
Delegated to: Matthieu Baerts
Headers show
Series mptcp: data checksum support | expand

Commit Message

Paolo Abeni May 4, 2021, 9:42 p.m. UTC 
From: Geliang Tang <geliangtang@gmail.com>

In mptcp_parse_option, adjust the expected_opsize, and parse the data
checksum value from the receiving DSS, then save it in mp_opt->csum.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
---
v3 -> v4:
 - drop unneeded brackets (geliang)
---
 net/mptcp/options.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)
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Patch

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 65ae62b6b391..3f43d48ee5bc 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -37,11 +37,10 @@  static void mptcp_parse_option(const struct sock *sk,
 	case MPTCPOPT_MP_CAPABLE:
 		/* strict size checking */
 		if (!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN)) {
-			if (skb->len > tcp_hdr(skb)->doff << 2) {
+			if (skb->len > tcp_hdr(skb)->doff << 2)
 				expected_opsize = TCPOLEN_MPTCP_MPC_ACK_DATA;
-			} else {
+			else
 				expected_opsize = TCPOLEN_MPTCP_MPC_ACK;
-			}
 		} else {
 			if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_ACK)
 				expected_opsize = TCPOLEN_MPTCP_MPC_SYNACK;
@@ -166,6 +165,7 @@  static void mptcp_parse_option(const struct sock *sk,
 		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);
+		mp_opt->csum_reqd = READ_ONCE(msk->csum_enabled);
 
 		pr_debug("data_fin=%d dsn64=%d use_map=%d ack64=%d use_ack=%d",
 			 mp_opt->data_fin, mp_opt->dsn64,
@@ -186,6 +186,9 @@  static void mptcp_parse_option(const struct sock *sk,
 				expected_opsize += TCPOLEN_MPTCP_DSS_MAP64;
 			else
 				expected_opsize += TCPOLEN_MPTCP_DSS_MAP32;
+
+			if (mp_opt->csum_reqd)
+				expected_opsize += TCPOLEN_MPTCP_DSS_CHECKSUM;
 		}
 
 		/* RFC 6824, Section 3.3:
@@ -193,8 +196,7 @@  static void mptcp_parse_option(const struct sock *sk,
 		 * 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)
+		if (opsize != expected_opsize)
 			break;
 
 		mp_opt->dss = 1;
@@ -226,9 +228,14 @@  static void mptcp_parse_option(const struct sock *sk,
 			mp_opt->data_len = get_unaligned_be16(ptr);
 			ptr += 2;
 
-			pr_debug("data_seq=%llu subflow_seq=%u data_len=%u",
+			if (mp_opt->csum_reqd) {
+				mp_opt->csum = (__force __sum16)get_unaligned_be16(ptr);
+				ptr += 2;
+			}
+
+			pr_debug("data_seq=%llu subflow_seq=%u data_len=%u csum=%u",
 				 mp_opt->data_seq, mp_opt->subflow_seq,
-				 mp_opt->data_len);
+				 mp_opt->data_len, mp_opt->csum);
 		}
 
 		break;