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ofp-actions: Add truncate action.

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The patch adds a new action to support packet truncation.  The new action
is formatted as 'output(port=n,max_len=m)', as output to port n, with
packet size being MIN(original_size, m).

One use case is to enable port mirroring to send smaller packets to the
destination port so that only useful packet information is mirrored/copied,
saving some performance overhead of copying entire packet payload.  Example
use case is below as well as shown in the testcases:

    - Output to port 1 with max_len 100 bytes.
    - The output packet size on port 1 will be MIN(original_packet_size, 100).
    # ovs-ofctl add-flow br0 'actions=output(port=1,max_len=100)'

    - The scope of max_len is limited to output action itself.  The following
      packet size of output:1 and output:2 will be intact.
    # ovs-ofctl add-flow br0 \
            'actions=output(port=1,max_len=100),output:1,output:2'
    - The Datapath actions shows:
    # Datapath actions: trunc(100),1,1,2

Tested-at: https://travis-ci.org/williamtu/ovs-travis/builds/140037134
Signed-off-by: William Tu <u9012063@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
This commit is contained in:
William Tu
2016-06-24 07:42:30 -07:00
committed by Pravin B Shelar
parent 4c7804f14b
commit aaca4fe0ce
27 changed files with 848 additions and 4 deletions
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65
lib/dp-packet.h
View File

@@ -60,6 +60,7 @@ struct dp_packet {
* or UINT16_MAX. */
uint16_t l4_ofs; /* Transport-level header offset,
or UINT16_MAX. */
uint32_t cutlen; /* length in bytes to cut from the end. */
union {
struct pkt_metadata md;
uint64_t data[DP_PACKET_CONTEXT_SIZE / 8];
@@ -494,6 +495,34 @@ dp_packet_set_allocated(struct dp_packet *b, uint16_t s)
}
#endif
static inline void
dp_packet_reset_cutlen(struct dp_packet *b)
{
b->cutlen = 0;
}
static inline uint32_t
dp_packet_set_cutlen(struct dp_packet *b, uint32_t max_len)
{
if (max_len < ETH_HEADER_LEN) {
max_len = ETH_HEADER_LEN;
}
if (max_len >= dp_packet_size(b)) {
b->cutlen = 0;
} else {
b->cutlen = dp_packet_size(b) - max_len;
}
return b->cutlen;
}
static inline uint32_t
dp_packet_get_cutlen(struct dp_packet *b)
{
/* Always in valid range if user uses dp_packet_set_cutlen. */
return b->cutlen;
}
static inline void *
dp_packet_data(const struct dp_packet *b)
{
@@ -567,12 +596,14 @@ enum { NETDEV_MAX_BURST = 32 }; /* Maximum number packets in a batch. */
struct dp_packet_batch {
int count;
bool trunc; /* true if the batch needs truncate. */
struct dp_packet *packets[NETDEV_MAX_BURST];
};
static inline void dp_packet_batch_init(struct dp_packet_batch *b)
{
b->count = 0;
b->trunc = false;
}
static inline void
@@ -585,12 +616,14 @@ dp_packet_batch_clone(struct dp_packet_batch *dst,
dst->packets[i] = dp_packet_clone(src->packets[i]);
}
dst->count = src->count;
dst->trunc = src->trunc;
}
static inline void
packet_batch_init_packet(struct dp_packet_batch *b, struct dp_packet *p)
{
b->count = 1;
b->trunc = false;
b->packets[0] = p;
}
@@ -606,6 +639,38 @@ dp_packet_delete_batch(struct dp_packet_batch *batch, bool may_steal)
}
}
static inline void
dp_packet_batch_apply_cutlen(struct dp_packet_batch *pktb)
{
int i;
if (!pktb->trunc)
return;
for (i = 0; i < pktb->count; i++) {
uint32_t cutlen = dp_packet_get_cutlen(pktb->packets[i]);
dp_packet_set_size(pktb->packets[i],
dp_packet_size(pktb->packets[i]) - cutlen);
dp_packet_reset_cutlen(pktb->packets[i]);
}
pktb->trunc = false;
}
static inline void
dp_packet_batch_reset_cutlen(struct dp_packet_batch *pktb)
{
int i;
if (!pktb->trunc)
return;
pktb->trunc = false;
for (i = 0; i < pktb->count; i++) {
dp_packet_reset_cutlen(pktb->packets[i]);
}
}
#ifdef __cplusplus
}
#endif