diff options
Diffstat (limited to 'net/rxrpc/input.c')
| -rw-r--r-- | net/rxrpc/input.c | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/net/rxrpc/input.c b/net/rxrpc/input.c index 4cc3b54ebc49..e65b230fce4c 100644 --- a/net/rxrpc/input.c +++ b/net/rxrpc/input.c @@ -815,6 +815,30 @@ static void rxrpc_input_soft_acks(struct rxrpc_call *call, u8 *acks, } /* + * Return true if the ACK is valid - ie. it doesn't appear to have regressed + * with respect to the ack state conveyed by preceding ACKs. + */ +static bool rxrpc_is_ack_valid(struct rxrpc_call *call, + rxrpc_seq_t first_pkt, rxrpc_seq_t prev_pkt) +{ + rxrpc_seq_t base = READ_ONCE(call->ackr_first_seq); + + if (after(first_pkt, base)) + return true; /* The window advanced */ + + if (before(first_pkt, base)) + return false; /* firstPacket regressed */ + + if (after_eq(prev_pkt, call->ackr_prev_seq)) + return true; /* previousPacket hasn't regressed. */ + + /* Some rx implementations put a serial number in previousPacket. */ + if (after_eq(prev_pkt, base + call->tx_winsize)) + return false; + return true; +} + +/* * Process an ACK packet. * * ack.firstPacket is the sequence number of the first soft-ACK'd/NAK'd packet @@ -878,8 +902,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb, } /* Discard any out-of-order or duplicate ACKs (outside lock). */ - if (before(first_soft_ack, call->ackr_first_seq) || - before(prev_pkt, call->ackr_prev_seq)) { + if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) { trace_rxrpc_rx_discard_ack(call->debug_id, sp->hdr.serial, first_soft_ack, call->ackr_first_seq, prev_pkt, call->ackr_prev_seq); @@ -895,8 +918,7 @@ static void rxrpc_input_ack(struct rxrpc_call *call, struct sk_buff *skb, spin_lock(&call->input_lock); /* Discard any out-of-order or duplicate ACKs (inside lock). */ - if (before(first_soft_ack, call->ackr_first_seq) || - before(prev_pkt, call->ackr_prev_seq)) { + if (!rxrpc_is_ack_valid(call, first_soft_ack, prev_pkt)) { trace_rxrpc_rx_discard_ack(call->debug_id, sp->hdr.serial, first_soft_ack, call->ackr_first_seq, prev_pkt, call->ackr_prev_seq); |