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User-Space MPLS actions and matches

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This patch implements use-space datapath and non-datapath code
to match and use the datapath API set out in Leo Alterman's patch
"user-space datapath: Add basic MPLS support to kernel".

The resulting MPLS implementation supports:
* Pushing a single MPLS label
* Poping a single MPLS label
* Modifying an MPLS lable using set-field or load actions
  that act on the label value, tc and bos bit.
* There is no support for manipulating the TTL
  this is considered future work.

The single-level push pop limitation is implemented by processing
push, pop and set-field/load actions in order and discarding information
that would require multiple levels of push/pop to be supported.

e.g.
   push,push -> the first push is discarded
   pop,pop -> the first pop is discarded

This patch is based heavily on work by Ravi K.

Cc: Ravi K <rkerur@gmail.com>
Reviewed-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Ben Pfaff <blp@nicira.com>
This commit is contained in:
Simon Horman
2013-01-25 16:22:07 +09:00
committed by Ben Pfaff
parent d224e35014
commit b02475c53b
29 changed files with 1223 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files

179
lib/packets.c
View File

@@ -192,7 +192,8 @@ eth_push_vlan(struct ofpbuf *packet, ovs_be16 tci)
/* Removes outermost VLAN header (if any is present) from 'packet'.
*
* 'packet->l2' must initially point to 'packet''s Ethernet header. */
* 'packet->l2_5' should initially point to 'packet''s outer-most MPLS header
* or may be NULL if there are no MPLS headers. */
void
eth_pop_vlan(struct ofpbuf *packet)
{
@@ -211,6 +212,182 @@ eth_pop_vlan(struct ofpbuf *packet)
}
}
/* Return depth of mpls stack.
*
* 'packet->l2_5' should initially point to 'packet''s outer-most MPLS header
* or may be NULL if there are no MPLS headers. */
uint16_t
eth_mpls_depth(const struct ofpbuf *packet)
{
struct mpls_hdr *mh = packet->l2_5;
uint16_t depth;
if (!mh) {
return 0;
}
depth = 0;
while (packet->size >= ((char *)mh - (char *)packet->data) + sizeof *mh) {
depth++;
if (mh->mpls_lse & htonl(MPLS_BOS_MASK)) {
break;
}
mh++;
}
return depth;
}
/* Set ethertype of the packet. */
void
set_ethertype(struct ofpbuf *packet, ovs_be16 eth_type)
{
struct eth_header *eh = packet->data;
if (eh->eth_type == htons(ETH_TYPE_VLAN)) {
ovs_be16 *p;
p = (ovs_be16 *)((char *)(packet->l2_5 ? packet->l2_5 : packet->l3) - 2);
*p = eth_type;
} else {
eh->eth_type = eth_type;
}
}
static bool is_mpls(struct ofpbuf *packet)
{
return packet->l2_5 != NULL;
}
/* Set time to live (TTL) of an MPLS label stack entry (LSE). */
static void
set_mpls_lse_ttl(ovs_be32 *lse, uint8_t ttl)
{
*lse &= ~htonl(MPLS_TTL_MASK);
*lse |= htonl((ttl << MPLS_TTL_SHIFT) & MPLS_TTL_MASK);
}
/* Set traffic class (TC) of an MPLS label stack entry (LSE). */
void
set_mpls_lse_tc(ovs_be32 *lse, uint8_t tc)
{
*lse &= ~htonl(MPLS_TC_MASK);
*lse |= htonl((tc << MPLS_TC_SHIFT) & MPLS_TC_MASK);
}
/* Set label of an MPLS label stack entry (LSE). */
void
set_mpls_lse_label(ovs_be32 *lse, ovs_be32 label)
{
*lse &= ~htonl(MPLS_LABEL_MASK);
*lse |= htonl((ntohl(label) << MPLS_LABEL_SHIFT) & MPLS_LABEL_MASK);
}
/* Set bottom of stack (BoS) bit of an MPLS label stack entry (LSE). */
void
set_mpls_lse_bos(ovs_be32 *lse, uint8_t bos)
{
*lse &= ~htonl(MPLS_BOS_MASK);
*lse |= htonl((bos << MPLS_BOS_SHIFT) & MPLS_BOS_MASK);
}
/* Compose an MPLS label stack entry (LSE) from its components:
* label, traffic class (TC), time to live (TTL) and
* bottom of stack (BoS) bit. */
ovs_be32
set_mpls_lse_values(uint8_t ttl, uint8_t tc, uint8_t bos, ovs_be32 label)
{
ovs_be32 lse = htonl(0);
set_mpls_lse_ttl(&lse, ttl);
set_mpls_lse_tc(&lse, tc);
set_mpls_lse_bos(&lse, bos);
set_mpls_lse_label(&lse, label);
return lse;
}
/* Push an new MPLS stack entry onto the MPLS stack and adjust 'packet->l2' and
* 'packet->l2_5' accordingly. The new entry will be the outermost entry on
* the stack.
*
* Previous to calling this function, 'packet->l2_5' must be set; if the MPLS
* label to be pushed will be the first label in 'packet', then it should be
* the same as 'packet->l3'. */
static void
push_mpls_lse(struct ofpbuf *packet, struct mpls_hdr *mh)
{
char * header;
size_t len;
header = ofpbuf_push_uninit(packet, MPLS_HLEN);
len = (char *)packet->l2_5 - (char *)packet->l2;
memmove(header, packet->l2, len);
memcpy(header + len, mh, sizeof *mh);
packet->l2 = (char*)packet->l2 - MPLS_HLEN;
packet->l2_5 = (char*)packet->l2_5 - MPLS_HLEN;
}
/* Set MPLS label stack entry to outermost MPLS header.*/
void
set_mpls_lse(struct ofpbuf *packet, ovs_be32 mpls_lse)
{
struct mpls_hdr *mh = packet->l2_5;
/* Packet type should be MPLS to set label stack entry. */
if (is_mpls(packet)) {
/* Update mpls label stack entry. */
mh->mpls_lse = mpls_lse;
}
}
/* Push MPLS label stack entry 'lse' onto 'packet' as the the outermost MPLS
* header. If 'packet' does not already have any MPLS labels, then its
* Ethertype is changed to 'ethtype' (which must be an MPLS Ethertype). */
void
push_mpls(struct ofpbuf *packet, ovs_be16 ethtype, ovs_be32 lse)
{
struct mpls_hdr mh;
if (!eth_type_mpls(ethtype)) {
return;
}
if (!is_mpls(packet)) {
/* Set ethtype and MPLS label stack entry. */
set_ethertype(packet, ethtype);
packet->l2_5 = packet->l3;
}
/* Push new MPLS shim header onto packet. */
mh.mpls_lse = lse;
push_mpls_lse(packet, &mh);
}
/* If 'packet' is an MPLS packet, removes its outermost MPLS label stack entry.
* If the label that was removed was the only MPLS label, changes 'packet''s
* Ethertype to 'ethtype' (which ordinarily should not be an MPLS
* Ethertype). */
void
pop_mpls(struct ofpbuf *packet, ovs_be16 ethtype)
{
struct mpls_hdr *mh = NULL;
if (is_mpls(packet)) {
size_t len;
mh = packet->l2_5;
len = (char*)packet->l2_5 - (char*)packet->l2;
/* If bottom of the stack set ethertype. */
if (mh->mpls_lse & htonl(MPLS_BOS_MASK)) {
packet->l2_5 = NULL;
set_ethertype(packet, ethtype);
} else {
packet->l2_5 = (char*)packet->l2_5 + MPLS_HLEN;
}
/* Shift the l2 header forward. */
memmove((char*)packet->data + MPLS_HLEN, packet->data, len);
packet->size -= MPLS_HLEN;
packet->data = (char*)packet->data + MPLS_HLEN;
packet->l2 = (char*)packet->l2 + MPLS_HLEN;
}
}
/* Converts hex digits in 'hex' to an Ethernet packet in '*packetp'. The
* caller must free '*packetp'. On success, returns NULL. On failure, returns
* an error message and stores NULL in '*packetp'. */