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Don't perform full route dumps when routes change.
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We used to perform a full route dump whenever the kernel notified
us that the kernel table has changed.  Avoid the dump, and only
install or flush the route that was notified by the kernel.

We still perform periodic route dumps every kernel_check_interval.
This can be set to 0 if periodic route dumps are too costly.
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@jech
jech committed Mar 17, 2023
1 parent 141cd28 commit 0842bb9
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Showing 3 changed files with 107 additions and 49 deletions.
15 changes: 3 additions & 12 deletions babeld.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -86,7 +86,6 @@ int protocol_port;
unsigned char protocol_group[16];
int protocol_socket = -1;
int kernel_socket = -1;
static int kernel_routes_changed = 0;
static int kernel_link_changed = 0;
static int kernel_addr_changed = 0;
int kernel_check_interval = 300;
Expand All @@ -99,12 +98,6 @@ static int accept_local_connections(void);
static void init_signals(void);
static void dump_tables(FILE *out);

static void
kernel_route_notify(int add, struct kernel_route *route, void *closure)
{
kernel_routes_changed = 1;
}

static void
kernel_addr_notify(int add, struct kernel_addr *addr, void *closure)
{
Expand Down Expand Up @@ -524,7 +517,6 @@ main(int argc, char **argv)
if(rc < 0)
fprintf(stderr, "Warning: couldn't check exported routes.\n");

kernel_routes_changed = 0;
kernel_link_changed = 0;
kernel_addr_changed = 0;
kernel_dump_time = now.tv_sec + roughly(kernel_check_interval);
Expand Down Expand Up @@ -689,13 +681,12 @@ main(int argc, char **argv)
kernel_link_changed = 0;
}

if(kernel_routes_changed || kernel_addr_changed ||
if(kernel_addr_changed ||
(kernel_check_interval > 0 && now.tv_sec >= kernel_dump_time)) {
rc = check_xroutes(1,
!kernel_routes_changed && !kernel_addr_changed);
rc = check_xroutes(1, !kernel_addr_changed);
if(rc < 0)
fprintf(stderr, "Warning: couldn't check exported routes.\n");
kernel_routes_changed = kernel_addr_changed = 0;
kernel_addr_changed = 0;
kernel_dump_time = now.tv_sec + roughly(kernel_check_interval);
}

Expand Down
138 changes: 102 additions & 36 deletions xroute.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -153,9 +153,18 @@ add_xroute(unsigned char prefix[16], unsigned char plen,
}

void
flush_xroute(struct xroute *xroute)
flush_xroute(struct xroute *xroute, int send_updates)
{
int i;
unsigned char prefix[16], plen;
unsigned char src_prefix[16], src_plen;
struct babel_route *route;

/* We'll use these after we free the xroute */
memcpy(prefix, xroute->prefix, 16);
plen = xroutes->plen;
memcpy(src_prefix, xroutes->src_prefix, 16);
src_plen = xroute->src_plen;

i = xroute - xroutes;
assert(i >= 0 && i < numxroutes);
Expand All @@ -181,6 +190,17 @@ flush_xroute(struct xroute *xroute)
xroutes = new_xroutes;
maxxroutes = n;
}

route = find_best_route(prefix, plen, src_prefix, src_plen, 1, NULL);
if(route != NULL && route_metric(route) < INFINITY &&
route_feasible(route)) {
install_route(route);
if(send_updates)
send_update(NULL, 0, prefix, plen, src_prefix, src_plen);
} else {
if(send_updates)
send_update_resend(NULL, prefix, plen, src_prefix, src_plen);
}
}

/* Returns an overestimate of the number of xroutes. */
Expand Down Expand Up @@ -335,6 +355,84 @@ kernel_route_compare(const void *v1, const void *v2)
return 0;
}

static void
modify_xroute(int i, struct kernel_route *kroute, int update) {
if(xroutes[i].metric != kroute->metric ||
xroutes[i].proto != kroute->proto) {
xroutes[i].metric = kroute->metric;
xroutes[i].proto = kroute->proto;
local_notify_xroute(&xroutes[i], LOCAL_CHANGE);
if(update)
send_update(NULL, 0, xroutes[i].prefix, xroutes[i].plen,
xroutes[i].src_prefix, xroutes[i].src_plen);
}
}

static void
flush_duplicate_route(struct kernel_route *kroute) {
struct babel_route *route;
route = find_installed_route(kroute->prefix, kroute->plen,
kroute->src_prefix, kroute->src_plen);
if(route) {
if(allow_duplicates < 0 || kroute->metric < allow_duplicates)
uninstall_route(route);
}
}


void
kernel_route_notify(int add, struct kernel_route *kroute, void *closure)
{
struct filter_result filter_result;
int i, rc;

debugf("Kernel route: %s %s",
add ? "add" : "del", format_prefix(kroute->prefix, kroute->plen));

kroute->metric = redistribute_filter(kroute->prefix, kroute->plen,
kroute->src_prefix, kroute->src_plen,
kroute->ifindex, kroute->proto,
&filter_result);

if(filter_result.src_prefix != NULL) {
memcpy(kroute->src_prefix, filter_result.src_prefix, 16);
kroute->src_plen = filter_result.src_plen;
}

if(kroute->metric >= INFINITY)
return;

i = find_xroute_slot(kroute->prefix, kroute->plen,
kroute->src_prefix, kroute->src_plen, NULL);
if(!add) {
if(i >= 0)
flush_xroute(&xroutes[i], 1);
else
debugf("Flushing unknown route.\n");
return;
}

if(i >= 0) {
modify_xroute(i, kroute, 1);
return;
}

if(martian_prefix(kroute->prefix, kroute->plen))
return;

rc = add_xroute(kroute->prefix, kroute->plen,
kroute->src_prefix, kroute->src_plen,
kroute->metric, kroute->ifindex,
kroute->proto);
if(rc > 0) {
flush_duplicate_route(kroute);
send_update(NULL, 0, kroute->prefix, kroute->plen,
kroute->src_prefix, kroute->src_plen);
}

}


int
check_xroutes(int send_updates, int warn)
{
Expand Down Expand Up @@ -417,16 +515,7 @@ check_xroutes(int send_updates, int warn)
routes[i].metric, routes[i].ifindex,
routes[i].proto);
if(rc > 0) {
struct babel_route *route;
route = find_installed_route(routes[i].prefix,
routes[i].plen,
routes[i].src_prefix,
routes[i].src_plen);
if(route) {
if(allow_duplicates < 0 ||
routes[i].metric < allow_duplicates)
uninstall_route(route);
}
flush_duplicate_route(&routes[i]);
if(send_updates)
send_update(NULL, 0, routes[i].prefix, routes[i].plen,
routes[i].src_prefix, routes[i].src_plen);
Expand All @@ -436,37 +525,14 @@ check_xroutes(int send_updates, int warn)
i++;
} else if(rc > 0) {
/* Flush xroute j. */
unsigned char prefix[16], plen;
unsigned char src_prefix[16], src_plen;
struct babel_route *route;
if(warn)
fprintf(stderr,
"Flushing spurious route to %s "
"(this shouldn't happen)\n",
format_prefix(xroutes[j].prefix, xroutes[j].plen));
memcpy(prefix, xroutes[j].prefix, 16);
plen = xroutes[j].plen;
memcpy(src_prefix, xroutes[j].src_prefix, 16);
src_plen = xroutes[j].src_plen;
flush_xroute(&xroutes[j]);
route = find_best_route(prefix, plen, src_prefix, src_plen,
1, NULL);
if(route != NULL) {
install_route(route);
send_update(NULL, 0, prefix, plen, src_prefix, src_plen);
} else {
send_update_resend(NULL, prefix, plen, src_prefix, src_plen);
}
flush_xroute(&xroutes[j], send_updates);
} else {
if(routes[i].metric != xroutes[j].metric ||
routes[i].proto != xroutes[j].proto) {
xroutes[j].metric = routes[i].metric;
xroutes[j].proto = routes[i].proto;
local_notify_xroute(&xroutes[j], LOCAL_CHANGE);
if(send_updates)
send_update(NULL, 0, xroutes[j].prefix, xroutes[j].plen,
xroutes[j].src_prefix, xroutes[j].src_plen);
}
modify_xroute(j, &routes[i], send_updates);
i++;
j++;
}
Expand Down
3 changes: 2 additions & 1 deletion xroute.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -37,11 +37,12 @@ struct xroute *find_xroute(const unsigned char *prefix, unsigned char plen,
int add_xroute(unsigned char prefix[16], unsigned char plen,
unsigned char src_prefix[16], unsigned char src_plen,
unsigned short metric, unsigned int ifindex, int proto);
void flush_xroute(struct xroute *xroute);
void flush_xroute(struct xroute *xroute, int send_update);
int xroutes_estimate(void);
struct xroute_stream *xroute_stream();
struct xroute *xroute_stream_next(struct xroute_stream *stream);
void xroute_stream_done(struct xroute_stream *stream);
int kernel_addresses(int ifindex, int ll,
struct kernel_route *routes, int maxroutes);
void kernel_route_notify(int add, struct kernel_route *route, void *closure);
int check_xroutes(int send_updates, int warn);

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