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bgpd: Handle Addpath capability using dynamic capabilities
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Changing Addpath type, and or disabling RX (receiving) flag, we can do this
without tearing down the session, and using dynamic capabilities.

Signed-off-by: Donatas Abraitis <[email protected]>
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@ton31337
ton31337 committed Oct 3, 2023
1 parent 51255e1 commit 05cf9d0
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Showing 5 changed files with 246 additions and 14 deletions.
33 changes: 32 additions & 1 deletion bgpd/bgp_addpath.c
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,8 @@

#include "bgp_addpath.h"
#include "bgp_route.h"
#include "bgp_open.h"
#include "bgp_packet.h"

static const struct bgp_addpath_strategy_names strat_names[BGP_ADDPATH_MAX] = {
{
Expand Down Expand Up @@ -359,6 +361,31 @@ void bgp_addpath_type_changed(struct bgp *bgp)
}
}

int bgp_addpath_capability_action(enum bgp_addpath_strat addpath_type,
uint8_t paths)
{
int action = CAPABILITY_ACTION_UNSET;

switch (addpath_type) {
case BGP_ADDPATH_ALL:
case BGP_ADDPATH_BEST_PER_AS:
action = CAPABILITY_ACTION_SET;
break;
case BGP_ADDPATH_BEST_SELECTED:
if (paths)
action = CAPABILITY_ACTION_SET;
else
action = CAPABILITY_ACTION_UNSET;
break;
case BGP_ADDPATH_NONE:
case BGP_ADDPATH_MAX:
action = CAPABILITY_ACTION_UNSET;
break;
}

return action;
}

/*
* Change the addpath type assigned to a peer, or peer group. In addition to
* adjusting the counts, peer sessions will be reset as needed to make the
Expand All @@ -373,6 +400,7 @@ void bgp_addpath_set_peer_type(struct peer *peer, afi_t afi, safi_t safi,
struct listnode *node, *nnode;
struct peer *tmp_peer;
struct peer_group *group;
int action = bgp_addpath_capability_action(addpath_type, paths);

if (safi == SAFI_LABELED_UNICAST)
safi = SAFI_UNICAST;
Expand Down Expand Up @@ -430,9 +458,12 @@ void bgp_addpath_set_peer_type(struct peer *peer, afi_t afi, safi_t safi,
}
}
} else {
peer_change_action(peer, afi, safi, peer_change_reset);
if (!CHECK_FLAG(peer->cap, PEER_CAP_DYNAMIC_RCV) &&
!CHECK_FLAG(peer->cap, PEER_CAP_DYNAMIC_ADV))
peer_change_action(peer, afi, safi, peer_change_reset);
}

bgp_capability_send(peer, afi, safi, CAPABILITY_CODE_ADDPATH, action);
}

/*
Expand Down
8 changes: 8 additions & 0 deletions bgpd/bgp_addpath.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -15,6 +15,12 @@
#include "bgpd/bgp_table.h"
#include "lib/json.h"

struct bgp_addpath_capability {
uint16_t afi;
uint8_t safi;
uint8_t flags;
};

#define BGP_ADDPATH_TX_ID_FOR_DEFAULT_ORIGINATE 1

void bgp_addpath_init_bgp_data(struct bgp_addpath_bgp_data *d);
Expand Down Expand Up @@ -57,4 +63,6 @@ void bgp_addpath_update_ids(struct bgp *bgp, struct bgp_dest *dest, afi_t afi,
safi_t safi);

void bgp_addpath_type_changed(struct bgp *bgp);
extern int bgp_addpath_capability_action(enum bgp_addpath_strat addpath_type,
uint8_t paths);
#endif
179 changes: 177 additions & 2 deletions bgpd/bgp_packet.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
#include "lib_errors.h"

#include "bgpd/bgpd.h"
#include "bgpd/bgp_addpath.h"
#include "bgpd/bgp_table.h"
#include "bgpd/bgp_dump.h"
#include "bgpd/bgp_bmp.h"
Expand Down Expand Up @@ -1216,6 +1217,8 @@ void bgp_capability_send(struct peer *peer, afi_t afi, safi_t safi,
unsigned long cap_len;
uint16_t len;
uint32_t gr_restart_time;
uint8_t addpath_afi_safi_count = 0;
bool adv_addpath_tx = false;
const char *capability = lookup_msg(capcode_str, capability_code,
"Unknown");

Expand Down Expand Up @@ -1379,11 +1382,91 @@ void bgp_capability_send(struct peer *peer, afi_t afi, safi_t safi,
capability, iana_afi2str(pkt_afi),
iana_safi2str(pkt_safi));
break;
case CAPABILITY_CODE_ADDPATH:
SET_FLAG(peer->cap, PEER_CAP_ADDPATH_ADV);

FOREACH_AFI_SAFI (afi, safi) {
if (peer->afc[afi][safi]) {
addpath_afi_safi_count++;

/* Only advertise addpath TX if a feature that
* will use it is
* configured */
if (peer->addpath_type[afi][safi] !=
BGP_ADDPATH_NONE)
adv_addpath_tx = true;

/* If we have enabled labeled unicast, we MUST check
* against unicast SAFI because addpath IDs are
* allocated under unicast SAFI, the same as the RIB
* is managed in unicast SAFI.
*/
if (safi == SAFI_LABELED_UNICAST)
if (peer->addpath_type[afi][SAFI_UNICAST] !=
BGP_ADDPATH_NONE)
adv_addpath_tx = true;
}
}

stream_putc(s, action);
stream_putc(s, CAPABILITY_CODE_ADDPATH);
stream_putc(s, CAPABILITY_CODE_ADDPATH_LEN *
addpath_afi_safi_count);

FOREACH_AFI_SAFI (afi, safi) {
if (peer->afc[afi][safi]) {
bool adv_addpath_rx =
!CHECK_FLAG(peer->af_flags[afi][safi],
PEER_FLAG_DISABLE_ADDPATH_RX);
uint8_t flags = 0;

/* Convert AFI, SAFI to values for packet. */
bgp_map_afi_safi_int2iana(afi, safi, &pkt_afi,
&pkt_safi);

stream_putw(s, pkt_afi);
stream_putc(s, pkt_safi);

if (adv_addpath_rx) {
SET_FLAG(flags, BGP_ADDPATH_RX);
SET_FLAG(peer->af_cap[afi][safi],
PEER_CAP_ADDPATH_AF_RX_ADV);
} else {
UNSET_FLAG(peer->af_cap[afi][safi],
PEER_CAP_ADDPATH_AF_RX_ADV);
}

if (adv_addpath_tx) {
SET_FLAG(flags, BGP_ADDPATH_TX);
SET_FLAG(peer->af_cap[afi][safi],
PEER_CAP_ADDPATH_AF_TX_ADV);
if (safi == SAFI_LABELED_UNICAST)
SET_FLAG(peer->af_cap[afi]
[SAFI_UNICAST],
PEER_CAP_ADDPATH_AF_TX_ADV);
} else {
UNSET_FLAG(peer->af_cap[afi][safi],
PEER_CAP_ADDPATH_AF_TX_ADV);
}

stream_putc(s, flags);
}
}

if (bgp_debug_neighbor_events(peer))
zlog_debug("%pBP sending CAPABILITY has %s %s for afi/safi: %s/%s",
peer,
action == CAPABILITY_ACTION_SET
? "Advertising"
: "Removing",
capability, iana_afi2str(pkt_afi),
iana_safi2str(pkt_safi));

break;
case CAPABILITY_CODE_REFRESH:
case CAPABILITY_CODE_ORF:
case CAPABILITY_CODE_AS4:
case CAPABILITY_CODE_DYNAMIC:
case CAPABILITY_CODE_ADDPATH:
case CAPABILITY_CODE_ENHANCED_RR:
case CAPABILITY_CODE_FQDN:
case CAPABILITY_CODE_ENHE:
Expand Down Expand Up @@ -2878,6 +2961,96 @@ static int bgp_route_refresh_receive(struct peer_connection *connection,
return BGP_PACKET_NOOP;
}

static void bgp_dynamic_capability_addpath(uint8_t *pnt, int action,
struct capability_header *hdr,
struct peer *peer)
{
uint8_t *data = pnt + 3;
uint8_t *end = data + hdr->length;
size_t len = end - data;
afi_t afi;
safi_t safi;

if (action == CAPABILITY_ACTION_SET) {
if (len % CAPABILITY_CODE_ADDPATH_LEN) {
flog_warn(EC_BGP_CAPABILITY_INVALID_LENGTH,
"Add Path: Received invalid length %zu, non-multiple of 4",
len);
return;
}

SET_FLAG(peer->cap, PEER_CAP_ADDPATH_RCV);

while (data + CAPABILITY_CODE_ADDPATH_LEN <= end) {
afi_t afi;
safi_t safi;
iana_afi_t pkt_afi;
iana_safi_t pkt_safi;
struct bgp_addpath_capability bac;

memcpy(&bac, data, sizeof(bac));
pkt_afi = ntohs(bac.afi);
pkt_safi = safi_int2iana(bac.safi);

if (bgp_debug_neighbor_events(peer))
zlog_debug("%s OPEN has %s capability for afi/safi: %s/%s%s%s",
peer->host,
lookup_msg(capcode_str, hdr->code,
NULL),
iana_afi2str(pkt_afi),
iana_safi2str(pkt_safi),
(bac.flags & BGP_ADDPATH_RX)
? ", receive"
: "",
(bac.flags & BGP_ADDPATH_TX)
? ", transmit"
: "");

if (bgp_map_afi_safi_iana2int(pkt_afi, pkt_safi, &afi,
&safi)) {
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s Addr-family %s/%s(afi/safi) not supported. Ignore the Addpath Attribute for this AFI/SAFI",
peer->host,
iana_afi2str(pkt_afi),
iana_safi2str(pkt_safi));
continue;
} else if (!peer->afc[afi][safi]) {
if (bgp_debug_neighbor_events(peer))
zlog_debug("%s Addr-family %s/%s(afi/safi) not enabled. Ignore the AddPath capability for this AFI/SAFI",
peer->host,
iana_afi2str(pkt_afi),
iana_safi2str(pkt_safi));
continue;
}

if (CHECK_FLAG(bac.flags, BGP_ADDPATH_RX))
SET_FLAG(peer->af_cap[afi][safi],
PEER_CAP_ADDPATH_AF_RX_RCV);
else
UNSET_FLAG(peer->af_cap[afi][safi],
PEER_CAP_ADDPATH_AF_RX_RCV);

if (CHECK_FLAG(bac.flags, BGP_ADDPATH_TX))
SET_FLAG(peer->af_cap[afi][safi],
PEER_CAP_ADDPATH_AF_TX_RCV);
else
UNSET_FLAG(peer->af_cap[afi][safi],
PEER_CAP_ADDPATH_AF_TX_RCV);

data += CAPABILITY_CODE_ADDPATH_LEN;
}
} else {
FOREACH_AFI_SAFI (afi, safi) {
UNSET_FLAG(peer->af_cap[afi][safi],
PEER_CAP_ADDPATH_AF_RX_RCV);
UNSET_FLAG(peer->af_cap[afi][safi],
PEER_CAP_ADDPATH_AF_TX_RCV);
}

UNSET_FLAG(peer->cap, PEER_CAP_ADDPATH_RCV);
}
}

static void bgp_dynamic_capability_llgr(uint8_t *pnt, int action,
struct capability_header *hdr,
struct peer *peer)
Expand Down Expand Up @@ -3232,11 +3405,13 @@ static int bgp_capability_msg_parse(struct peer *peer, uint8_t *pnt,
case CAPABILITY_CODE_LLGR:
bgp_dynamic_capability_llgr(pnt, action, hdr, peer);
break;
case CAPABILITY_CODE_ADDPATH:
bgp_dynamic_capability_addpath(pnt, action, hdr, peer);
break;
case CAPABILITY_CODE_REFRESH:
case CAPABILITY_CODE_ORF:
case CAPABILITY_CODE_AS4:
case CAPABILITY_CODE_DYNAMIC:
case CAPABILITY_CODE_ADDPATH:
case CAPABILITY_CODE_ENHANCED_RR:
case CAPABILITY_CODE_FQDN:
case CAPABILITY_CODE_ENHE:
Expand Down
38 changes: 28 additions & 10 deletions bgpd/bgp_vty.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -8925,13 +8925,21 @@ DEFUN(neighbor_disable_addpath_rx,
struct peer *peer;
afi_t afi = bgp_node_afi(vty);
safi_t safi = bgp_node_safi(vty);
int ret;
int action;

peer = peer_and_group_lookup_vty(vty, peer_str);
if (!peer)
return CMD_WARNING_CONFIG_FAILED;

return peer_af_flag_set_vty(vty, peer_str, afi, safi,
PEER_FLAG_DISABLE_ADDPATH_RX);
action = bgp_addpath_capability_action(peer->addpath_type[afi][safi], 0);

ret = peer_af_flag_set_vty(vty, peer_str, afi, safi,
PEER_FLAG_DISABLE_ADDPATH_RX);

bgp_capability_send(peer, afi, safi, CAPABILITY_CODE_ADDPATH, action);

return ret;
}

DEFUN(no_neighbor_disable_addpath_rx,
Expand All @@ -8946,13 +8954,21 @@ DEFUN(no_neighbor_disable_addpath_rx,
struct peer *peer;
afi_t afi = bgp_node_afi(vty);
safi_t safi = bgp_node_safi(vty);
int ret;
int action;

peer = peer_and_group_lookup_vty(vty, peer_str);
if (!peer)
return CMD_WARNING_CONFIG_FAILED;

return peer_af_flag_unset_vty(vty, peer_str, afi, safi,
PEER_FLAG_DISABLE_ADDPATH_RX);
action = bgp_addpath_capability_action(peer->addpath_type[afi][safi], 0);

ret = peer_af_flag_unset_vty(vty, peer_str, afi, safi,
PEER_FLAG_DISABLE_ADDPATH_RX);

bgp_capability_send(peer, afi, safi, CAPABILITY_CODE_ADDPATH, action);

return ret;
}

DEFUN (neighbor_addpath_tx_all_paths,
Expand All @@ -8964,13 +8980,15 @@ DEFUN (neighbor_addpath_tx_all_paths,
{
int idx_peer = 1;
struct peer *peer;
afi_t afi = bgp_node_afi(vty);
safi_t safi = bgp_node_safi(vty);

peer = peer_and_group_lookup_vty(vty, argv[idx_peer]->arg);
if (!peer)
return CMD_WARNING_CONFIG_FAILED;

bgp_addpath_set_peer_type(peer, bgp_node_afi(vty), bgp_node_safi(vty),
BGP_ADDPATH_ALL, 0);
bgp_addpath_set_peer_type(peer, afi, safi, BGP_ADDPATH_ALL, 0);

return CMD_SUCCESS;
}

Expand All @@ -8990,20 +9008,20 @@ DEFUN (no_neighbor_addpath_tx_all_paths,
{
int idx_peer = 2;
struct peer *peer;
afi_t afi = bgp_node_afi(vty);
safi_t safi = bgp_node_safi(vty);

peer = peer_and_group_lookup_vty(vty, argv[idx_peer]->arg);
if (!peer)
return CMD_WARNING_CONFIG_FAILED;

if (peer->addpath_type[bgp_node_afi(vty)][bgp_node_safi(vty)]
!= BGP_ADDPATH_ALL) {
if (peer->addpath_type[afi][safi] != BGP_ADDPATH_ALL) {
vty_out(vty,
"%% Peer not currently configured to transmit all paths.");
return CMD_WARNING_CONFIG_FAILED;
}

bgp_addpath_set_peer_type(peer, bgp_node_afi(vty), bgp_node_safi(vty),
BGP_ADDPATH_NONE, 0);
bgp_addpath_set_peer_type(peer, afi, safi, BGP_ADDPATH_NONE, 0);

return CMD_SUCCESS;
}
Expand Down
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