Commit cc9d2566986692e5b6df1aac88fbf65fe340d432
Committed by
David S. Miller
David S. Miller
1 parent
926bdeab55
mptcp: update per unacked sequence on pkt reception
So that we keep per unacked sequence number consistent; since we update per msk data, use an atomic64 cmpxchg() to protect against concurrent updates from multiple subflows. Initialize the snd_una at connect()/accept() time. Co-developed-by: Florian Westphal <fw@strlen.de> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Showing 3 changed files with 49 additions and 6 deletions Side-by-side Diff
net/mptcp/options.c
| ... | ... | @@ -744,6 +744,46 @@ |
| 744 | 744 | return true; |
| 745 | 745 | } |
| 746 | 746 | |
| 747 | +static u64 expand_ack(u64 old_ack, u64 cur_ack, bool use_64bit) | |
| 748 | +{ | |
| 749 | + u32 old_ack32, cur_ack32; | |
| 750 | + | |
| 751 | + if (use_64bit) | |
| 752 | + return cur_ack; | |
| 753 | + | |
| 754 | + old_ack32 = (u32)old_ack; | |
| 755 | + cur_ack32 = (u32)cur_ack; | |
| 756 | + cur_ack = (old_ack & GENMASK_ULL(63, 32)) + cur_ack32; | |
| 757 | + if (unlikely(before(cur_ack32, old_ack32))) | |
| 758 | + return cur_ack + (1LL << 32); | |
| 759 | + return cur_ack; | |
| 760 | +} | |
| 761 | + | |
| 762 | +static void update_una(struct mptcp_sock *msk, | |
| 763 | + struct mptcp_options_received *mp_opt) | |
| 764 | +{ | |
| 765 | + u64 new_snd_una, snd_una, old_snd_una = atomic64_read(&msk->snd_una); | |
| 766 | + u64 write_seq = READ_ONCE(msk->write_seq); | |
| 767 | + | |
| 768 | + /* avoid ack expansion on update conflict, to reduce the risk of | |
| 769 | + * wrongly expanding to a future ack sequence number, which is way | |
| 770 | + * more dangerous than missing an ack | |
| 771 | + */ | |
| 772 | + new_snd_una = expand_ack(old_snd_una, mp_opt->data_ack, mp_opt->ack64); | |
| 773 | + | |
| 774 | + /* ACK for data not even sent yet? Ignore. */ | |
| 775 | + if (after64(new_snd_una, write_seq)) | |
| 776 | + new_snd_una = old_snd_una; | |
| 777 | + | |
| 778 | + while (after64(new_snd_una, old_snd_una)) { | |
| 779 | + snd_una = old_snd_una; | |
| 780 | + old_snd_una = atomic64_cmpxchg(&msk->snd_una, snd_una, | |
| 781 | + new_snd_una); | |
| 782 | + if (old_snd_una == snd_una) | |
| 783 | + break; | |
| 784 | + } | |
| 785 | +} | |
| 786 | + | |
| 747 | 787 | static bool add_addr_hmac_valid(struct mptcp_sock *msk, |
| 748 | 788 | struct mptcp_options_received *mp_opt) |
| 749 | 789 | { |
| ... | ... | @@ -805,6 +845,12 @@ |
| 805 | 845 | if (!mp_opt->dss) |
| 806 | 846 | return; |
| 807 | 847 | |
| 848 | + /* we can't wait for recvmsg() to update the ack_seq, otherwise | |
| 849 | + * monodirectional flows will stuck | |
| 850 | + */ | |
| 851 | + if (mp_opt->use_ack) | |
| 852 | + update_una(msk, mp_opt); | |
| 853 | + | |
| 808 | 854 | mpext = skb_ext_add(skb, SKB_EXT_MPTCP); |
| 809 | 855 | if (!mpext) |
| 810 | 856 | return; |
| ... | ... | @@ -829,12 +875,6 @@ |
| 829 | 875 | } |
| 830 | 876 | mpext->data_len = mp_opt->data_len; |
| 831 | 877 | mpext->use_map = 1; |
| 832 | - } | |
| 833 | - | |
| 834 | - if (mp_opt->use_ack) { | |
| 835 | - mpext->data_ack = mp_opt->data_ack; | |
| 836 | - mpext->use_ack = 1; | |
| 837 | - mpext->ack64 = mp_opt->ack64; | |
| 838 | 878 | } |
| 839 | 879 | |
| 840 | 880 | mpext->data_fin = mp_opt->data_fin; |
net/mptcp/protocol.c
| ... | ... | @@ -906,6 +906,7 @@ |
| 906 | 906 | } |
| 907 | 907 | |
| 908 | 908 | msk->write_seq = subflow_req->idsn + 1; |
| 909 | + atomic64_set(&msk->snd_una, msk->write_seq); | |
| 909 | 910 | if (subflow_req->remote_key_valid) { |
| 910 | 911 | msk->can_ack = true; |
| 911 | 912 | msk->remote_key = subflow_req->remote_key; |
| ... | ... | @@ -1107,6 +1108,7 @@ |
| 1107 | 1108 | WRITE_ONCE(msk->write_seq, subflow->idsn + 1); |
| 1108 | 1109 | WRITE_ONCE(msk->ack_seq, ack_seq); |
| 1109 | 1110 | WRITE_ONCE(msk->can_ack, 1); |
| 1111 | + atomic64_set(&msk->snd_una, msk->write_seq); | |
| 1110 | 1112 | |
| 1111 | 1113 | mptcp_pm_new_connection(msk, 0); |
| 1112 | 1114 | } |