mptcp: send out checksum for DSS

In mptcp_write_options, if the checksum is enabled, adjust the option
length and send out the data checksum with DSS suboption.

Co-developed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index b4da08d..1468774 100644 (file)
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -478,6 +478,9 @@ static bool mptcp_established_options_mp(struct sock *sk, struct sk_buff *skb,
                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->ext_copy.data_seq = mpext->data_seq;
+                               opts->ext_copy.subflow_seq = mpext->subflow_seq;
                                opts->ext_copy.csum = mpext->csum;
                                len += TCPOLEN_MPTCP_DSS_CHECKSUM;
                        }
@@ -545,18 +548,21 @@ static bool mptcp_established_options_dss(struct sock *sk, struct sk_buff *skb,
        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;
+               unsigned int map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
 
-               map_size = TCPOLEN_MPTCP_DSS_BASE + TCPOLEN_MPTCP_DSS_MAP64;
+               if (mpext) {
+                       if (opts->csum_reqd)
+                               map_size += TCPOLEN_MPTCP_DSS_CHECKSUM;
 
-               remaining -= map_size;
-               dss_size = map_size;
-               if (mpext)
                        opts->ext_copy = *mpext;
+               }
 
+               remaining -= map_size;
+               dss_size = map_size;
                if (skb && snd_data_fin_enable)
                        mptcp_write_data_fin(subflow, skb, &opts->ext_copy);
                ret = true;
@@ -1346,6 +1352,9 @@ mp_capable_done:
                        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);
@@ -1365,8 +1374,13 @@ mp_capable_done:
                        ptr += 2;
                        put_unaligned_be32(mpext->subflow_seq, ptr);
                        ptr += 1;
-                       put_unaligned_be32(mpext->data_len << 16 |
-                                          TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
+                       if (opts->csum_reqd) {
+                               put_unaligned_be32(mpext->data_len << 16 |
+                                                  mptcp_make_csum(mpext), ptr);
+                       } else {
+                               put_unaligned_be32(mpext->data_len << 16 |
+                                                  TCPOPT_NOP << 8 | TCPOPT_NOP, ptr);
+                       }
                }
        }