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rxrpc: Use info in skbuff instead of reparsing a jumbo packet

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Use the information now cached in the skbuff private data to avoid the need
to reparse a jumbo packet.  We can find all the subpackets by dead
reckoning, so it's only necessary to note how many there are, whether the
last one is flagged as LAST_PACKET and whether any have the REQUEST_ACK
flag set.

This is necessary as once recvmsg() can see the packet, it can start
modifying it, such as doing in-place decryption.

Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2019-08-27 09:51:30 +01:00
parent c3c9e3df49
commit e2de6c4048
3 changed files with 138 additions and 135 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

3
net/rxrpc/ar-internal.h
View file

@ -617,8 +617,7 @@ struct rxrpc_call {
#define RXRPC_TX_ANNO_LAST 0x04
#define RXRPC_TX_ANNO_RESENT 0x08
#define RXRPC_RX_ANNO_JUMBO 0x3f /* Jumbo subpacket number + 1 if not zero */
#define RXRPC_RX_ANNO_JLAST 0x40 /* Set if last element of a jumbo packet */
#define RXRPC_RX_ANNO_SUBPACKET 0x3f /* Subpacket number in jumbogram */
#define RXRPC_RX_ANNO_VERIFIED 0x80 /* Set if verified and decrypted */
rxrpc_seq_t tx_hard_ack; /* Dead slot in buffer; the first transmitted but
* not hard-ACK'd packet follows this.

229
net/rxrpc/input.c
View file

@ -405,10 +405,10 @@ static bool rxrpc_validate_data(struct sk_buff *skb)
* (that information is encoded in the ACK packet).
*/
static void rxrpc_input_dup_data(struct rxrpc_call *call, rxrpc_seq_t seq,
u8 annotation, bool *_jumbo_bad)
bool is_jumbo, bool *_jumbo_bad)
{
/* Discard normal packets that are duplicates. */
if (annotation == 0)
if (is_jumbo)
return;
/* Skip jumbo subpackets that are duplicates. When we've had three or
@ -428,19 +428,17 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
enum rxrpc_call_state state;
unsigned int offset = sizeof(struct rxrpc_wire_header);
unsigned int ix;
unsigned int j;
rxrpc_serial_t serial = sp->hdr.serial, ack_serial = 0;
rxrpc_seq_t seq = sp->hdr.seq, hard_ack;
bool immediate_ack = false, jumbo_bad = false, queued;
u16 len;
u8 ack = 0, flags, annotation = 0;
rxrpc_seq_t seq0 = sp->hdr.seq, hard_ack;
bool immediate_ack = false, jumbo_bad = false;
u8 ack = 0;
_enter("{%u,%u},{%u,%u}",
call->rx_hard_ack, call->rx_top, skb->len, seq);
call->rx_hard_ack, call->rx_top, skb->len, seq0);
_proto("Rx DATA %%%u { #%u f=%02x }",
sp->hdr.serial, seq, sp->hdr.flags);
_proto("Rx DATA %%%u { #%u f=%02x n=%u }",
sp->hdr.serial, seq0, sp->hdr.flags, sp->nr_subpackets);
state = READ_ONCE(call->state);
if (state >= RXRPC_CALL_COMPLETE)
@ -469,137 +467,136 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
!rxrpc_receiving_reply(call))
goto unlock;
call->ackr_prev_seq = seq;
call->ackr_prev_seq = seq0;
hard_ack = READ_ONCE(call->rx_hard_ack);
if (after(seq, hard_ack + call->rx_winsize)) {
ack = RXRPC_ACK_EXCEEDS_WINDOW;
ack_serial = serial;
goto ack;
}
flags = sp->hdr.flags;
if (flags & RXRPC_JUMBO_PACKET) {
if (sp->nr_subpackets > 1) {
if (call->nr_jumbo_bad > 3) {
ack = RXRPC_ACK_NOSPACE;
ack_serial = serial;
goto ack;
}
annotation = 1;
}
next_subpacket:
queued = false;
ix = seq & RXRPC_RXTX_BUFF_MASK;
len = skb->len;
if (flags & RXRPC_JUMBO_PACKET)
len = RXRPC_JUMBO_DATALEN;
for (j = 0; j < sp->nr_subpackets; j++) {
rxrpc_serial_t serial = sp->hdr.serial + j;
rxrpc_seq_t seq = seq0 + j;
unsigned int ix = seq & RXRPC_RXTX_BUFF_MASK;
bool terminal = (j == sp->nr_subpackets - 1);
bool last = terminal && (sp->rx_flags & RXRPC_SKB_INCL_LAST);
u8 flags, annotation = j;
if (flags & RXRPC_LAST_PACKET) {
if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
seq != call->rx_top) {
rxrpc_proto_abort("LSN", call, seq);
goto unlock;
_proto("Rx DATA+%u %%%u { #%x t=%u l=%u }",
j, serial, seq, terminal, last);
if (last) {
if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
seq != call->rx_top) {
rxrpc_proto_abort("LSN", call, seq);
goto unlock;
}
} else {
if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
after_eq(seq, call->rx_top)) {
rxrpc_proto_abort("LSA", call, seq);
goto unlock;
}
}
} else {
if (test_bit(RXRPC_CALL_RX_LAST, &call->flags) &&
after_eq(seq, call->rx_top)) {
rxrpc_proto_abort("LSA", call, seq);
goto unlock;
}
}
trace_rxrpc_rx_data(call->debug_id, seq, serial, flags, annotation);
if (before_eq(seq, hard_ack)) {
ack = RXRPC_ACK_DUPLICATE;
ack_serial = serial;
goto skip;
}
flags = 0;
if (last)
flags |= RXRPC_LAST_PACKET;
if (!terminal)
flags |= RXRPC_JUMBO_PACKET;
if (test_bit(j, sp->rx_req_ack))
flags |= RXRPC_REQUEST_ACK;
trace_rxrpc_rx_data(call->debug_id, seq, serial, flags, annotation);
if (flags & RXRPC_REQUEST_ACK && !ack) {
ack = RXRPC_ACK_REQUESTED;
ack_serial = serial;
}
if (call->rxtx_buffer[ix]) {
rxrpc_input_dup_data(call, seq, annotation, &jumbo_bad);
if (ack != RXRPC_ACK_DUPLICATE) {
if (before_eq(seq, hard_ack)) {
ack = RXRPC_ACK_DUPLICATE;
ack_serial = serial;
continue;
}
immediate_ack = true;
goto skip;
}
/* Queue the packet. We use a couple of memory barriers here as need
* to make sure that rx_top is perceived to be set after the buffer
* pointer and that the buffer pointer is set after the annotation and
* the skb data.
*
* Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
* and also rxrpc_fill_out_ack().
*/
rxrpc_get_skb(skb, rxrpc_skb_rx_got);
call->rxtx_annotations[ix] = annotation;
smp_wmb();
call->rxtx_buffer[ix] = skb;
if (after(seq, call->rx_top)) {
smp_store_release(&call->rx_top, seq);
} else if (before(seq, call->rx_top)) {
/* Send an immediate ACK if we fill in a hole */
if (!ack) {
ack = RXRPC_ACK_DELAY;
ack_serial = serial;
if (call->rxtx_buffer[ix]) {
rxrpc_input_dup_data(call, seq, sp->nr_subpackets > 1,
&jumbo_bad);
if (ack != RXRPC_ACK_DUPLICATE) {
ack = RXRPC_ACK_DUPLICATE;
ack_serial = serial;
}
immediate_ack = true;
continue;
}
immediate_ack = true;
}
if (flags & RXRPC_LAST_PACKET) {
set_bit(RXRPC_CALL_RX_LAST, &call->flags);
trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
} else {
trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
}
queued = true;
if (after_eq(seq, call->rx_expect_next)) {
if (after(seq, call->rx_expect_next)) {
_net("OOS %u > %u", seq, call->rx_expect_next);
ack = RXRPC_ACK_OUT_OF_SEQUENCE;
ack_serial = serial;
}
call->rx_expect_next = seq + 1;
}
skip:
offset += len;
if (flags & RXRPC_JUMBO_PACKET) {
if (skb_copy_bits(skb, offset, &flags, 1) < 0) {
rxrpc_proto_abort("XJF", call, seq);
goto unlock;
}
offset += sizeof(struct rxrpc_jumbo_header);
seq++;
serial++;
annotation++;
if (flags & RXRPC_JUMBO_PACKET)
annotation |= RXRPC_RX_ANNO_JLAST;
if (after(seq, hard_ack + call->rx_winsize)) {
ack = RXRPC_ACK_EXCEEDS_WINDOW;
ack_serial = serial;
if (!jumbo_bad) {
call->nr_jumbo_bad++;
jumbo_bad = true;
if (flags & RXRPC_JUMBO_PACKET) {
if (!jumbo_bad) {
call->nr_jumbo_bad++;
jumbo_bad = true;
}
}
goto ack;
}
_proto("Rx DATA Jumbo %%%u", serial);
goto next_subpacket;
}
if (flags & RXRPC_REQUEST_ACK && !ack) {
ack = RXRPC_ACK_REQUESTED;
ack_serial = serial;
}
if (queued && flags & RXRPC_LAST_PACKET && !ack) {
ack = RXRPC_ACK_DELAY;
ack_serial = serial;
/* Queue the packet. We use a couple of memory barriers here as need
* to make sure that rx_top is perceived to be set after the buffer
* pointer and that the buffer pointer is set after the annotation and
* the skb data.
*
* Barriers against rxrpc_recvmsg_data() and rxrpc_rotate_rx_window()
* and also rxrpc_fill_out_ack().
*/
rxrpc_get_skb(skb, rxrpc_skb_rx_got);
call->rxtx_annotations[ix] = annotation;
smp_wmb();
call->rxtx_buffer[ix] = skb;
if (after(seq, call->rx_top)) {
smp_store_release(&call->rx_top, seq);
} else if (before(seq, call->rx_top)) {
/* Send an immediate ACK if we fill in a hole */
if (!ack) {
ack = RXRPC_ACK_DELAY;
ack_serial = serial;
}
immediate_ack = true;
}
if (terminal) {
/* From this point on, we're not allowed to touch the
* packet any longer as its ref now belongs to the Rx
* ring.
*/
skb = NULL;
}
if (last) {
set_bit(RXRPC_CALL_RX_LAST, &call->flags);
if (!ack) {
ack = RXRPC_ACK_DELAY;
ack_serial = serial;
}
trace_rxrpc_receive(call, rxrpc_receive_queue_last, serial, seq);
} else {
trace_rxrpc_receive(call, rxrpc_receive_queue, serial, seq);
}
if (after_eq(seq, call->rx_expect_next)) {
if (after(seq, call->rx_expect_next)) {
_net("OOS %u > %u", seq, call->rx_expect_next);
ack = RXRPC_ACK_OUT_OF_SEQUENCE;
ack_serial = serial;
}
call->rx_expect_next = seq + 1;
}
}
ack:
@ -612,7 +609,7 @@ static void rxrpc_input_data(struct rxrpc_call *call, struct sk_buff *skb)
false, true,
rxrpc_propose_ack_input_data);
if (sp->hdr.seq == READ_ONCE(call->rx_hard_ack) + 1) {
if (seq0 == READ_ONCE(call->rx_hard_ack) + 1) {
trace_rxrpc_notify_socket(call->debug_id, serial);
rxrpc_notify_socket(call);
}

41
net/rxrpc/recvmsg.c
View file

@ -177,7 +177,8 @@ static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
struct sk_buff *skb;
rxrpc_serial_t serial;
rxrpc_seq_t hard_ack, top;
u8 flags;
bool last = false;
u8 subpacket;
int ix;
_enter("%d", call->debug_id);
@ -191,10 +192,13 @@ static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
skb = call->rxtx_buffer[ix];
rxrpc_see_skb(skb, rxrpc_skb_rx_rotated);
sp = rxrpc_skb(skb);
flags = sp->hdr.flags;
serial = sp->hdr.serial;
if (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO)
serial += (call->rxtx_annotations[ix] & RXRPC_RX_ANNO_JUMBO) - 1;
subpacket = call->rxtx_annotations[ix] & RXRPC_RX_ANNO_SUBPACKET;
serial = sp->hdr.serial + subpacket;
if (subpacket == sp->nr_subpackets - 1 &&
sp->rx_flags & RXRPC_SKB_INCL_LAST)
last = true;
call->rxtx_buffer[ix] = NULL;
call->rxtx_annotations[ix] = 0;
@ -203,9 +207,8 @@ static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
rxrpc_free_skb(skb, rxrpc_skb_rx_freed);
_debug("%u,%u,%02x", hard_ack, top, flags);
trace_rxrpc_receive(call, rxrpc_receive_rotate, serial, hard_ack);
if (flags & RXRPC_LAST_PACKET) {
if (last) {
rxrpc_end_rx_phase(call, serial);
} else {
/* Check to see if there's an ACK that needs sending. */
@ -233,18 +236,19 @@ static int rxrpc_verify_packet(struct rxrpc_call *call, struct sk_buff *skb,
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
rxrpc_seq_t seq = sp->hdr.seq;
u16 cksum = sp->hdr.cksum;
u8 subpacket = annotation & RXRPC_RX_ANNO_SUBPACKET;
_enter("");
/* For all but the head jumbo subpacket, the security checksum is in a
* jumbo header immediately prior to the data.
*/
if ((annotation & RXRPC_RX_ANNO_JUMBO) > 1) {
if (subpacket > 0) {
__be16 tmp;
if (skb_copy_bits(skb, offset - 2, &tmp, 2) < 0)
BUG();
cksum = ntohs(tmp);
seq += (annotation & RXRPC_RX_ANNO_JUMBO) - 1;
seq += subpacket;
}
return call->conn->security->verify_packet(call, skb, offset, len,
@ -265,19 +269,18 @@ static int rxrpc_locate_data(struct rxrpc_call *call, struct sk_buff *skb,
u8 *_annotation,
unsigned int *_offset, unsigned int *_len)
{
struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
unsigned int offset = sizeof(struct rxrpc_wire_header);
unsigned int len;
int ret;
u8 annotation = *_annotation;
u8 subpacket = annotation & RXRPC_RX_ANNO_SUBPACKET;
/* Locate the subpacket */
offset += subpacket * RXRPC_JUMBO_SUBPKTLEN;
len = skb->len - offset;
if ((annotation & RXRPC_RX_ANNO_JUMBO) > 0) {
offset += (((annotation & RXRPC_RX_ANNO_JUMBO) - 1) *
RXRPC_JUMBO_SUBPKTLEN);
len = (annotation & RXRPC_RX_ANNO_JLAST) ?
skb->len - offset : RXRPC_JUMBO_SUBPKTLEN;
}
if (subpacket < sp->nr_subpackets - 1)
len = RXRPC_JUMBO_DATALEN;
if (!(annotation & RXRPC_RX_ANNO_VERIFIED)) {
ret = rxrpc_verify_packet(call, skb, annotation, offset, len);
@ -303,6 +306,7 @@ static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call,
{
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
rxrpc_serial_t serial;
rxrpc_seq_t hard_ack, top, seq;
size_t remain;
bool last;
@ -339,9 +343,12 @@ static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call,
rxrpc_see_skb(skb, rxrpc_skb_rx_seen);
sp = rxrpc_skb(skb);
if (!(flags & MSG_PEEK))
if (!(flags & MSG_PEEK)) {
serial = sp->hdr.serial;
serial += call->rxtx_annotations[ix] & RXRPC_RX_ANNO_SUBPACKET;
trace_rxrpc_receive(call, rxrpc_receive_front,
sp->hdr.serial, seq);
serial, seq);
}
if (msg)
sock_recv_timestamp(msg, sock->sk, skb);