Update the netdev_class so that struct ofpbuf * is passed to rx_recv()
to provide both the data and size of the data to read a packet into.
On success, update struct ofpbuf size inside netdev_class rx_recv
implementation and return 0. This moves logic from the caller.
On error a negative error code is returned, this behaviour is unchanged
by this patch.
This patch should not have any behavioural changes.
This patch is in preparation for the netdev-linux variant of rx_recv()
making use of headroom in the struct ofpbuf * parameter to push a VLAN tag
obtained from auxdata.
Signed-off-by: Simon Horman <ho...@verge.net.au>
---
v3
* On success, update struct ofpbuf size inside netdev_class rx_recv
implementation and return 0. This moves logic from the caller.
* Document that it is recommended that the struct ofpbuf should provide
extra tailroom for a VLAN header. This will be used by a subsequent patch.
* Update BSD code
v2
* First post
---
lib/netdev-bsd.c | 24 ++++++++++++++----------
lib/netdev-dummy.c | 9 +++++----
lib/netdev-linux.c | 16 ++++++++++------
lib/netdev-provider.h | 18 ++++++++++++------
lib/netdev.c | 4 +---
5 files changed, 42 insertions(+), 29 deletions(-)
diff --git a/lib/netdev-bsd.c b/lib/netdev-bsd.c
index 442c384..37b2a02 100644
--- a/lib/netdev-bsd.c
+++ b/lib/netdev-bsd.c
@@ -568,20 +568,21 @@ proc_pkt(u_char *args_, const struct pcap_pkthdr *hdr,
const u_char *packet)
* from rx->pcap.
*/
static int
-netdev_rx_bsd_recv_pcap(struct netdev_rx_bsd *rx, void *data, size_t size)
+netdev_rx_bsd_recv_pcap(struct netdev_rx_bsd *rx, struct ofpbuf *buffer)
{
struct pcap_arg arg;
int ret;
/* prepare the pcap argument to store the packet */
- arg.size = size;
- arg.data = data;
+ arg.size = ofpbuf_tailroom(buffer);
+ arg.data = buffer->data;
for (;;) {
ret = pcap_dispatch(rx->pcap_handle, 1, proc_pkt, (u_char *) &arg);
if (ret > 0) {
- return arg.retval; /* arg.retval < 0 is handled in the caller */
+ buffer->size += retval;
+ return 0;
}
if (ret == -1) {
if (errno == EINTR) {
@@ -599,12 +600,15 @@ netdev_rx_bsd_recv_pcap(struct netdev_rx_bsd *rx, void
*data, size_t size)
* 'rx->fd' is initialized with the tap file descriptor.
*/
static int
-netdev_rx_bsd_recv_tap(struct netdev_rx_bsd *rx, void *data, size_t size)
+netdev_rx_bsd_recv_tap(struct netdev_rx_bsd *rx, struct ofpbuf *buffer)
{
+ size_t size = ofpbuf_tailroom(buffer);
+
for (;;) {
- ssize_t retval = read(rx->fd, data, size);
+ ssize_t retval = read(rx->fd, buffer->data, size);
if (retval >= 0) {
- return retval;
+ buffer->size += retval;
+ return 0;
} else if (errno != EINTR) {
if (errno != EAGAIN) {
VLOG_WARN_RL(&rl, "error receiving Ethernet packet on %s: %s",
@@ -616,13 +620,13 @@ netdev_rx_bsd_recv_tap(struct netdev_rx_bsd *rx, void
*data, size_t size)
}
static int
-netdev_bsd_rx_recv(struct netdev_rx *rx_, void *data, size_t size)
+netdev_bsd_rx_recv(struct netdev_rx *rx_, struct ofpbuf *buffer)
{
struct netdev_rx_bsd *rx = netdev_rx_bsd_cast(rx_);
return (rx->pcap_handle
- ? netdev_rx_bsd_recv_pcap(rx, data, size)
- : netdev_rx_bsd_recv_tap(rx, data, size));
+ ? netdev_rx_bsd_recv_pcap(rx, buffer)
+ : netdev_rx_bsd_recv_tap(rx, buffer));
}
/*
diff --git a/lib/netdev-dummy.c b/lib/netdev-dummy.c
index 9515021..51b77db 100644
--- a/lib/netdev-dummy.c
+++ b/lib/netdev-dummy.c
@@ -445,7 +445,7 @@ netdev_dummy_rx_dealloc(struct netdev_rx *rx_)
}
static int
-netdev_dummy_rx_recv(struct netdev_rx *rx_, void *buffer, size_t size)
+netdev_dummy_rx_recv(struct netdev_rx *rx_, struct ofpbuf *buffer)
{
struct netdev_rx_dummy *rx = netdev_rx_dummy_cast(rx_);
struct netdev_dummy *netdev = netdev_dummy_cast(rx->up.netdev);
@@ -465,9 +465,10 @@ netdev_dummy_rx_recv(struct netdev_rx *rx_, void *buffer,
size_t size)
return -EAGAIN;
}
- if (packet->size <= size) {
- memcpy(buffer, packet->data, packet->size);
- retval = packet->size;
+ if (packet->size <= ofpbuf_tailroom(buffer)) {
+ memcpy(buffer->data, packet->data, packet->size);
+ buffer->size += packet->size;
+ retval = 0;
ovs_mutex_lock(&netdev->mutex);
netdev->stats.rx_packets++;
diff --git a/lib/netdev-linux.c b/lib/netdev-linux.c
index 9bdbbdf..ffaaa3b 100644
--- a/lib/netdev-linux.c
+++ b/lib/netdev-linux.c
@@ -849,25 +849,29 @@ netdev_linux_rx_dealloc(struct netdev_rx *rx_)
}
static int
-netdev_linux_rx_recv(struct netdev_rx *rx_, void *data, size_t size)
+netdev_linux_rx_recv(struct netdev_rx *rx_, struct ofpbuf *buffer)
{
struct netdev_rx_linux *rx = netdev_rx_linux_cast(rx_);
ssize_t retval;
+ size_t size = ofpbuf_tailroom(buffer);
do {
retval = (rx->is_tap
- ? read(rx->fd, data, size)
- : recv(rx->fd, data, size, MSG_TRUNC));
+ ? read(rx->fd, buffer->data, size)
+ : recv(rx->fd, buffer->data, size, MSG_TRUNC));
} while (retval < 0 && errno == EINTR);
- if (retval >= 0) {
- return retval > size ? -EMSGSIZE : retval;
- } else {
+ if (retval < 0) {
if (errno != EAGAIN) {
VLOG_WARN_RL(&rl, "error receiving Ethernet packet on %s: %s",
ovs_strerror(errno), netdev_rx_get_name(rx_));
}
return -errno;
+ } else if (retval > size) {
+ return -EMSGSIZE;
+ } else {
+ buffer->size += retval;
+ return 0;
}
}
diff --git a/lib/netdev-provider.h b/lib/netdev-provider.h
index 40ba944..6eec315 100644
--- a/lib/netdev-provider.h
+++ b/lib/netdev-provider.h
@@ -634,16 +634,22 @@ struct netdev_class {
void (*rx_destruct)(struct netdev_rx *);
void (*rx_dealloc)(struct netdev_rx *);
- /* Attempts to receive a packet from 'rx' into the 'size' bytes in
- * 'buffer'. If successful, returns the number of bytes in the received
- * packet, otherwise a negative errno value. Returns -EAGAIN immediately
- * if no packet is ready to be received.
+ /* Attempts to receive a packet from 'rx' into 'buffer'.
+ * If successful, returns 0 and increments the 'size' field of 'buffer'
+ * by the number of bytes in the received packet, otherwise a negative
+ * errno value. Returns -EAGAIN immediately if no packet is ready to
+ * be received.
*
* Must return -EMSGSIZE, and discard the packet, if the received packet
- * is longer than 'size' bytes.
+ * is longer than the tailroom of 'buffer'.
+ *
+ * It is advised that the tailroom of 'buffer' should be
+ * VLAN_HEADER_LEN bytes longer than the expected maximum packet size
+ * to allow space for an out of band VLAN header to be added to the
+ * packet.
*
* Specify NULL if this */
- int (*rx_recv)(struct netdev_rx *rx, void *buffer, size_t size);
+ int (*rx_recv)(struct netdev_rx *rx, struct ofpbuf *buffer);
/* Registers with the poll loop to wake up from the next call to
* poll_block() when a packet is ready to be received with netdev_rx_recv()
diff --git a/lib/netdev.c b/lib/netdev.c
index 1bcd80f..276bf84 100644
--- a/lib/netdev.c
+++ b/lib/netdev.c
@@ -550,11 +550,9 @@ netdev_rx_recv(struct netdev_rx *rx, struct ofpbuf *buffer)
ovs_assert(buffer->size == 0);
ovs_assert(ofpbuf_tailroom(buffer) >= ETH_TOTAL_MIN);
- retval = rx->netdev->netdev_class->rx_recv(rx, buffer->data,
- ofpbuf_tailroom(buffer));
+ retval = rx->netdev->netdev_class->rx_recv(rx, buffer);
if (retval >= 0) {
COVERAGE_INC(netdev_received);
- buffer->size += retval;
if (buffer->size < ETH_TOTAL_MIN) {
ofpbuf_put_zeros(buffer, ETH_TOTAL_MIN - buffer->size);
}
--
1.8.4
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