[AF_RXRPC]: Sort out MTU handling.
Sort out the MTU determination and handling in AF_RXRPC:
(1) If it's present, parse the additional information supplied by the peer at
the end of the ACK packet (struct ackinfo) to determine the MTU sizes
that peer is willing to support.
(2) Initialise the MTU size to that peer from the kernel's routing records.
(3) Send ACKs rather than ACKALLs as the former carry the additional info,
and the latter do not.
(4) Declare the interface MTU size in outgoing ACKs as a maximum amount of
data that can be stuffed into an RxRPC packet without it having to be
fragmented to come in this computer's NIC.
(5) If sendmsg() is given MSG_MORE then it should allocate an skb of the
maximum size rather than one just big enough for the data it's got left
to process on the theory that there is more data to come that it can
append to that packet.
This means, for example, that if AFS does a large StoreData op, all the
packets barring the last will be filled to the maximum unfragmented size.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rxrpc/ar-ack.c b/net/rxrpc/ar-ack.c
index fc07a92..657ee69 100644
--- a/net/rxrpc/ar-ack.c
+++ b/net/rxrpc/ar-ack.c
@@ -543,6 +543,38 @@
}
/*
+ * process the extra information that may be appended to an ACK packet
+ */
+static void rxrpc_extract_ackinfo(struct rxrpc_call *call, struct sk_buff *skb,
+ unsigned latest, int nAcks)
+{
+ struct rxrpc_ackinfo ackinfo;
+ struct rxrpc_peer *peer;
+ unsigned mtu;
+
+ if (skb_copy_bits(skb, nAcks + 3, &ackinfo, sizeof(ackinfo)) < 0) {
+ _leave(" [no ackinfo]");
+ return;
+ }
+
+ _proto("Rx ACK %%%u Info { rx=%u max=%u rwin=%u jm=%u }",
+ latest,
+ ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU),
+ ntohl(ackinfo.rwind), ntohl(ackinfo.jumbo_max));
+
+ mtu = min(ntohl(ackinfo.rxMTU), ntohl(ackinfo.maxMTU));
+
+ peer = call->conn->trans->peer;
+ if (mtu < peer->maxdata) {
+ spin_lock_bh(&peer->lock);
+ peer->maxdata = mtu;
+ peer->mtu = mtu + peer->hdrsize;
+ spin_unlock_bh(&peer->lock);
+ _net("Net MTU %u (maxdata %u)", peer->mtu, peer->maxdata);
+ }
+}
+
+/*
* process packets in the reception queue
*/
static int rxrpc_process_rx_queue(struct rxrpc_call *call,
@@ -606,6 +638,8 @@
rxrpc_acks[ack.reason],
ack.nAcks);
+ rxrpc_extract_ackinfo(call, skb, latest, ack.nAcks);
+
if (ack.reason == RXRPC_ACK_PING) {
_proto("Rx ACK %%%u PING Request", latest);
rxrpc_propose_ACK(call, RXRPC_ACK_PING_RESPONSE,
@@ -801,9 +835,9 @@
struct msghdr msg;
struct kvec iov[5];
unsigned long bits;
- __be32 data;
+ __be32 data, pad;
size_t len;
- int genbit, loop, nbit, ioc, ret;
+ int genbit, loop, nbit, ioc, ret, mtu;
u32 abort_code = RX_PROTOCOL_ERROR;
u8 *acks = NULL;
@@ -899,9 +933,30 @@
}
if (test_bit(RXRPC_CALL_ACK_FINAL, &call->events)) {
- hdr.type = RXRPC_PACKET_TYPE_ACKALL;
genbit = RXRPC_CALL_ACK_FINAL;
- goto send_message;
+
+ ack.bufferSpace = htons(8);
+ ack.maxSkew = 0;
+ ack.serial = 0;
+ ack.reason = RXRPC_ACK_IDLE;
+ ack.nAcks = 0;
+ call->ackr_reason = 0;
+
+ spin_lock_bh(&call->lock);
+ ack.serial = call->ackr_serial;
+ ack.previousPacket = call->ackr_prev_seq;
+ ack.firstPacket = htonl(call->rx_data_eaten + 1);
+ spin_unlock_bh(&call->lock);
+
+ pad = 0;
+
+ iov[1].iov_base = &ack;
+ iov[1].iov_len = sizeof(ack);
+ iov[2].iov_base = &pad;
+ iov[2].iov_len = 3;
+ iov[3].iov_base = &ackinfo;
+ iov[3].iov_len = sizeof(ackinfo);
+ goto send_ACK;
}
if (call->events & ((1 << RXRPC_CALL_RCVD_BUSY) |
@@ -971,8 +1026,6 @@
/* consider sending an ordinary ACK */
if (test_bit(RXRPC_CALL_ACK, &call->events)) {
- __be32 pad;
-
_debug("send ACK: window: %d - %d { %lx }",
call->rx_data_eaten, call->ackr_win_top,
call->ackr_window[0]);
@@ -997,12 +1050,6 @@
ack.serial = 0;
ack.reason = 0;
- ackinfo.rxMTU = htonl(5692);
-// ackinfo.rxMTU = htonl(call->conn->trans->peer->maxdata);
- ackinfo.maxMTU = htonl(call->conn->trans->peer->maxdata);
- ackinfo.rwind = htonl(32);
- ackinfo.jumbo_max = htonl(4);
-
spin_lock_bh(&call->lock);
ack.reason = call->ackr_reason;
ack.serial = call->ackr_serial;
@@ -1116,6 +1163,15 @@
ack.maxSkew = htons(atomic_read(&call->conn->hi_serial) -
ntohl(ack.serial));
send_ACK:
+ mtu = call->conn->trans->peer->if_mtu;
+ mtu -= call->conn->trans->peer->hdrsize;
+ ackinfo.maxMTU = htonl(mtu);
+ ackinfo.rwind = htonl(32);
+
+ /* permit the peer to send us jumbo packets if it wants to */
+ ackinfo.rxMTU = htonl(5692);
+ ackinfo.jumbo_max = htonl(4);
+
hdr.serial = htonl(atomic_inc_return(&call->conn->serial));
_proto("Tx ACK %%%u { m=%hu f=#%u p=#%u s=%%%u r=%s n=%u }",
ntohl(hdr.serial),