[PATCH net-next 1/9] rxrpc: Don't store the rxrpc header in the Tx queue sk_buffs

David Howells
2016-09-22T00:39:21Z

Don't store the rxrpc protocol header in sk_buffs on the transmit queue,
but rather generate it on the fly and pass it to kernel_sendmsg() as a
separate iov. This reduces the amount of storage required.

Note that the security header is still stored in the sk_buff as it may get
encrypted along with the data (and doesn't change with each transmission).

Signed-off-by: David Howells <dhowells@redhat.com>
---

net/rxrpc/ar-internal.h | 5 +--
net/rxrpc/call_event.c | 11 +-----
net/rxrpc/conn_object.c | 1 -
net/rxrpc/output.c | 83 ++++++++++++++++++++++++++++++++---------------
net/rxrpc/rxkad.c | 8 ++---
net/rxrpc/sendmsg.c | 51 +++++------------------------
6 files changed, 71 insertions(+), 88 deletions(-)

diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 034f525f2235..f021df4a6a22 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -385,10 +385,9 @@ struct rxrpc_connection {
int debug_id; /* debug ID for printks */
atomic_t serial; /* packet serial number counter */
unsigned int hi_serial; /* highest serial number received */
+ u32 security_nonce; /* response re-use preventer */
u8 size_align; /* data size alignment (for security) */
- u8 header_size; /* rxrpc + security header size */
u8 security_size; /* security header size */
- u32 security_nonce; /* response re-use preventer */
u8 security_ix; /* security type */
u8 out_clientflag; /* RXRPC_CLIENT_INITIATED if we are client */
};
@@ -946,7 +945,7 @@ extern const s8 rxrpc_ack_priority[];
* output.c
*/
int rxrpc_send_call_packet(struct rxrpc_call *, u8);
-int rxrpc_send_data_packet(struct rxrpc_connection *, struct sk_buff *);
+int rxrpc_send_data_packet(struct rxrpc_call *, struct sk_buff *);
void rxrpc_reject_packets(struct rxrpc_local *);

/*
diff --git a/net/rxrpc/call_event.c b/net/rxrpc/call_event.c
index 7d1b99824ed9..6247ce25eb21 100644
--- a/net/rxrpc/call_event.c
+++ b/net/rxrpc/call_event.c
@@ -139,7 +139,6 @@ void rxrpc_propose_ACK(struct rxrpc_call *call, u8 ack_reason,
*/
static void rxrpc_resend(struct rxrpc_call *call)
{
- struct rxrpc_wire_header *whdr;
struct rxrpc_skb_priv *sp;
struct sk_buff *skb;
rxrpc_seq_t cursor, seq, top;
@@ -201,15 +200,8 @@ static void rxrpc_resend(struct rxrpc_call *call)
skb = call->rxtx_buffer[ix];
rxrpc_get_skb(skb, rxrpc_skb_tx_got);
spin_unlock_bh(&call->lock);
- sp = rxrpc_skb(skb);
-
- /* Each Tx packet needs a new serial number */
- sp->hdr.serial = atomic_inc_return(&call->conn->serial);

- whdr = (struct rxrpc_wire_header *)skb->head;
- whdr->serial = htonl(sp->hdr.serial);
-
- if (rxrpc_send_data_packet(call->conn, skb) < 0) {
+ if (rxrpc_send_data_packet(call, skb) < 0) {
call->resend_at = now + 2;
rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
return;
@@ -217,6 +209,7 @@ static void rxrpc_resend(struct rxrpc_call *call)

if (rxrpc_is_client_call(call))
rxrpc_expose_client_call(call);
+ sp = rxrpc_skb(skb);
sp->resend_at = now + rxrpc_resend_timeout;

rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
diff --git a/net/rxrpc/conn_object.c b/net/rxrpc/conn_object.c
index 3b55aee0c436..e1e83af47866 100644
--- a/net/rxrpc/conn_object.c
+++ b/net/rxrpc/conn_object.c
@@ -53,7 +53,6 @@ struct rxrpc_connection *rxrpc_alloc_connection(gfp_t gfp)
spin_lock_init(&conn->state_lock);
conn->debug_id = atomic_inc_return(&rxrpc_debug_id);
conn->size_align = 4;
- conn->header_size = sizeof(struct rxrpc_wire_header);
conn->idle_timestamp = jiffies;
}

diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 16e18a94ffa6..817fb0e82d6a 100644
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -208,19 +208,42 @@ out:
/*
* send a packet through the transport endpoint
*/
-int rxrpc_send_data_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
+int rxrpc_send_data_packet(struct rxrpc_call *call, struct sk_buff *skb)
{
- struct kvec iov[1];
+ struct rxrpc_connection *conn = call->conn;
+ struct rxrpc_wire_header whdr;
+ struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
struct msghdr msg;
+ struct kvec iov[2];
+ rxrpc_serial_t serial;
+ size_t len;
int ret, opt;

_enter(",{%d}", skb->len);

- iov[0].iov_base = skb->head;
- iov[0].iov_len = skb->len;
+ /* Each transmission of a Tx packet needs a new serial number */
+ serial = atomic_inc_return(&conn->serial);
+
+ whdr.epoch = htonl(conn->proto.epoch);
+ whdr.cid = htonl(call->cid);
+ whdr.callNumber = htonl(call->call_id);
+ whdr.seq = htonl(sp->hdr.seq);
+ whdr.serial = htonl(serial);
+ whdr.type = RXRPC_PACKET_TYPE_DATA;
+ whdr.flags = sp->hdr.flags;
+ whdr.userStatus = 0;
+ whdr.securityIndex = call->security_ix;
+ whdr._rsvd = htons(sp->hdr._rsvd);
+ whdr.serviceId = htons(call->service_id);
+
+ iov[0].iov_base = &whdr;
+ iov[0].iov_len = sizeof(whdr);
+ iov[1].iov_base = skb->head;
+ iov[1].iov_len = skb->len;
+ len = iov[0].iov_len + iov[1].iov_len;

- msg.msg_name = &conn->params.peer->srx.transport;
- msg.msg_namelen = conn->params.peer->srx.transport_len;
+ msg.msg_name = &call->peer->srx.transport;
+ msg.msg_namelen = call->peer->srx.transport_len;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_flags = 0;
@@ -234,26 +257,33 @@ int rxrpc_send_data_packet(struct rxrpc_connection *conn, struct sk_buff *skb)
}
}

+ _proto("Tx DATA %%%u { #%u }", serial, sp->hdr.seq);
+
/* send the packet with the don't fragment bit set if we currently
* think it's small enough */
- if (skb->len - sizeof(struct rxrpc_wire_header) < conn->params.peer->maxdata) {
- down_read(&conn->params.local->defrag_sem);
- /* send the packet by UDP
- * - returns -EMSGSIZE if UDP would have to fragment the packet
- * to go out of the interface
- * - in which case, we'll have processed the ICMP error
- * message and update the peer record
- */
- ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
- iov[0].iov_len);
-
- up_read(&conn->params.local->defrag_sem);
- if (ret == -EMSGSIZE)
- goto send_fragmentable;
-
- _leave(" = %d [%u]", ret, conn->params.peer->maxdata);
- return ret;
+ if (iov[1].iov_len >= call->peer->maxdata)
+ goto send_fragmentable;
+
+ down_read(&conn->params.local->defrag_sem);
+ /* send the packet by UDP
+ * - returns -EMSGSIZE if UDP would have to fragment the packet
+ * to go out of the interface
+ * - in which case, we'll have processed the ICMP error
+ * message and update the peer record
+ */
+ ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 2, len);
+
+ up_read(&conn->params.local->defrag_sem);
+ if (ret == -EMSGSIZE)
+ goto send_fragmentable;
+
+done:
+ if (ret == 0) {
+ sp->resend_at = jiffies + rxrpc_resend_timeout;
+ sp->hdr.serial = serial;
}
+ _leave(" = %d [%u]", ret, call->peer->maxdata);
+ return ret;

send_fragmentable:
/* attempt to send this message with fragmentation enabled */
@@ -268,8 +298,8 @@ send_fragmentable:
SOL_IP, IP_MTU_DISCOVER,
(char *)&opt, sizeof(opt));
if (ret == 0) {
- ret = kernel_sendmsg(conn->params.local->socket, &msg, iov, 1,
- iov[0].iov_len);
+ ret = kernel_sendmsg(conn->params.local->socket, &msg,
+ iov, 2, len);

opt = IP_PMTUDISC_DO;
kernel_setsockopt(conn->params.local->socket, SOL_IP,
@@ -298,8 +328,7 @@ send_fragmentable:
}

up_write(&conn->params.local->defrag_sem);
- _leave(" = %d [frag %u]", ret, conn->params.peer->maxdata);
- return ret;
+ goto done;
}

/*
diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index ae392558829d..88d080a1a3de 100644
--- a/net/rxrpc/rxkad.c
+++ b/net/rxrpc/rxkad.c
@@ -80,12 +80,10 @@ static int rxkad_init_connection_security(struct rxrpc_connection *conn)
case RXRPC_SECURITY_AUTH:
conn->size_align = 8;
conn->security_size = sizeof(struct rxkad_level1_hdr);
- conn->header_size += sizeof(struct rxkad_level1_hdr);
break;
case RXRPC_SECURITY_ENCRYPT:
conn->size_align = 8;
conn->security_size = sizeof(struct rxkad_level2_hdr);
- conn->header_size += sizeof(struct rxkad_level2_hdr);
break;
default:
ret = -EKEYREJECTED;
@@ -161,7 +159,7 @@ static int rxkad_secure_packet_auth(const struct rxrpc_call *call,

_enter("");

- check = sp->hdr.seq ^ sp->hdr.callNumber;
+ check = sp->hdr.seq ^ call->call_id;
data_size |= (u32)check << 16;

hdr.data_size = htonl(data_size);
@@ -205,7 +203,7 @@ static int rxkad_secure_packet_encrypt(const struct rxrpc_call *call,

_enter("");

- check = sp->hdr.seq ^ sp->hdr.callNumber;
+ check = sp->hdr.seq ^ call->call_id;

rxkhdr.data_size = htonl(data_size | (u32)check << 16);
rxkhdr.checksum = 0;
@@ -277,7 +275,7 @@ static int rxkad_secure_packet(struct rxrpc_call *call,
/* calculate the security checksum */
x = (call->cid & RXRPC_CHANNELMASK) << (32 - RXRPC_CIDSHIFT);
x |= sp->hdr.seq & 0x3fffffff;
- call->crypto_buf[0] = htonl(sp->hdr.callNumber);
+ call->crypto_buf[0] = htonl(call->call_id);
call->crypto_buf[1] = htonl(x);

sg_init_one(&sg, call->crypto_buf, 8);
diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index 6a39ee97a0b7..814b17f23971 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -134,13 +134,11 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
write_unlock_bh(&call->state_lock);
}

- _proto("Tx DATA %%%u { #%u }", sp->hdr.serial, sp->hdr.seq);
-
if (seq == 1 && rxrpc_is_client_call(call))
rxrpc_expose_client_call(call);

sp->resend_at = jiffies + rxrpc_resend_timeout;
- ret = rxrpc_send_data_packet(call->conn, skb);
+ ret = rxrpc_send_data_packet(call, skb);
if (ret < 0) {
_debug("need instant resend %d", ret);
rxrpc_instant_resend(call, ix);
@@ -151,29 +149,6 @@ static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
}

/*
- * Convert a host-endian header into a network-endian header.
- */
-static void rxrpc_insert_header(struct sk_buff *skb)
-{
- struct rxrpc_wire_header whdr;
- struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
-
- whdr.epoch = htonl(sp->hdr.epoch);
- whdr.cid = htonl(sp->hdr.cid);
- whdr.callNumber = htonl(sp->hdr.callNumber);
- whdr.seq = htonl(sp->hdr.seq);
- whdr.serial = htonl(sp->hdr.serial);
- whdr.type = sp->hdr.type;
- whdr.flags = sp->hdr.flags;
- whdr.userStatus = sp->hdr.userStatus;
- whdr.securityIndex = sp->hdr.securityIndex;
- whdr._rsvd = htons(sp->hdr._rsvd);
- whdr.serviceId = htons(sp->hdr.serviceId);
-
- memcpy(skb->head, &whdr, sizeof(whdr));
-}
-
-/*
* send data through a socket
* - must be called in process context
* - caller holds the socket locked
@@ -232,7 +207,7 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,
space = chunk + call->conn->size_align;
space &= ~(call->conn->size_align - 1UL);

- size = space + call->conn->header_size;
+ size = space + call->conn->security_size;

_debug("SIZE: %zu/%zu/%zu", chunk, space, size);

@@ -248,9 +223,9 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,

ASSERTCMP(skb->mark, ==, 0);

- _debug("HS: %u", call->conn->header_size);
- skb_reserve(skb, call->conn->header_size);
- skb->len += call->conn->header_size;
+ _debug("HS: %u", call->conn->security_size);
+ skb_reserve(skb, call->conn->security_size);
+ skb->len += call->conn->security_size;

sp = rxrpc_skb(skb);
sp->remain = chunk;
@@ -312,33 +287,23 @@ static int rxrpc_send_data(struct rxrpc_sock *rx,

seq = call->tx_top + 1;

- sp->hdr.epoch = conn->proto.epoch;
- sp->hdr.cid = call->cid;
- sp->hdr.callNumber = call->call_id;
sp->hdr.seq = seq;
- sp->hdr.serial = atomic_inc_return(&conn->serial);
- sp->hdr.type = RXRPC_PACKET_TYPE_DATA;
- sp->hdr.userStatus = 0;
- sp->hdr.securityIndex = call->security_ix;
sp->hdr._rsvd = 0;
- sp->hdr.serviceId = call->service_id;
+ sp->hdr.flags = conn->out_clientflag;

- sp->hdr.flags = conn->out_clientflag;
if (msg_data_left(msg) == 0 && !more)
sp->hdr.flags |= RXRPC_LAST_PACKET;
else if (call->tx_top - call->tx_hard_ack <
call->tx_winsize)
sp->hdr.flags |= RXRPC_MORE_PACKETS;
- if (more && seq & 1)
+ if (seq & 1)
sp->hdr.flags |= RXRPC_REQUEST_ACK;

ret = conn->security->secure_packet(
- call, skb, skb->mark,
- skb->head + sizeof(struct rxrpc_wire_header));
+ call, skb, skb->mark, skb->head);
if (ret < 0)
goto out;

- rxrpc_insert_header(skb);
rxrpc_queue_packet(call, skb, !msg_data_left(msg) && !more);
skb = NULL;
}