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patricia: always mask prefixes before insertion #220

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8 changes: 7 additions & 1 deletion lib/utils/bgpstream_utils_patricia.c
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Original file line number Diff line number Diff line change
Expand Up @@ -645,6 +645,13 @@ bgpstream_patricia_tree_insert(bgpstream_patricia_tree_t *pt,
bgpstream_addr_version_t v = pfx->address.version;
bgpstream_patricia_node_t *node_it = bgpstream_patricia_get_head(pt, v);

/* Be kind and mask off any trailing bits in the provided prefix */
uint8_t bitlen = pfx->mask_len;
bgpstream_pfx_t pfxclean;
bgpstream_pfx_copy(&pfxclean, pfx);
bgpstream_addr_mask(&pfxclean.address, bitlen);
pfx = &pfxclean;

/* if Patricia Tree is empty, then insert new node */
if (node_it == NULL) {
if ((new_node = bgpstream_patricia_node_create(pt, pfx)) == NULL) {
Expand All @@ -663,7 +670,6 @@ bgpstream_patricia_tree_insert(bgpstream_patricia_tree_t *pt,

node_it = bpt_find_insert_point(node_it, pfx, &relation, &differ_bit);

uint8_t bitlen = pfx->mask_len;
if (relation == BGPSTREAM_PATRICIA_SELF) {
/* check the node contains an actual prefix,
* i.e. it is not a glue node */
Expand Down
111 changes: 110 additions & 1 deletion test/bgpstream-test-utils-patricia.c
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
#include "bgpstream_test.h"

#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <stdio.h>
Expand All @@ -48,6 +49,54 @@
#define IPV6_TEST_PFX_B_CHILD "2001:48d0:101:501:beef::/96"
#define IPV6_TEST_64_CNT 65537

// does NOT mask off trailing bits in the resulting prefix
// copied from bgpstream_str2pfx
static bgpstream_pfx_t *str2pfx_raw(const char *pfx_str, bgpstream_pfx_t *pfx)
{
if (pfx_str == NULL || pfx == NULL) {
return NULL;
}

char pfx_copy[INET6_ADDRSTRLEN + 3];
char *endptr = NULL;

/* strncpy() functions copy at most len characters from src into
* dst. If src is less than len characters long, the remainder of
* dst is filled with `\0' characters. Otherwise, dst is not
* terminated. */
strncpy(pfx_copy, pfx_str, INET6_ADDRSTRLEN + 3);
if (pfx_copy[INET6_ADDRSTRLEN + 3 - 1] != '\0') {
return NULL;
}

/* get pointer to ip/mask divisor */
char *found = strchr(pfx_copy, '/');
if (found == NULL) {
return NULL;
}

*found = '\0';
/* get the ip address */
if (bgpstream_str2addr(pfx_copy, &pfx->address) == NULL) {
return NULL;
}

/* get the mask len */
errno = 0;
unsigned long int r = strtoul(found + 1, &endptr, 10);
int ret = errno;
if (!(endptr != NULL && *endptr == '\0') || ret != 0 ||
(pfx->address.version == BGPSTREAM_ADDR_VERSION_IPV4 && r > 32) ||
(pfx->address.version == BGPSTREAM_ADDR_VERSION_IPV6 && r > 128)) {
return NULL;
}
pfx->mask_len = (uint8_t)r;
pfx->allowed_matches = BGPSTREAM_PREFIX_MATCH_ANY;

return pfx;
}


static int test_patricia()
{
bgpstream_patricia_tree_t *pt;
Expand All @@ -59,7 +108,7 @@ static int test_patricia()
int count6 = 0;

// Convenience macros
#define s2p(str) bgpstream_str2pfx((str), &pfx)
#define s2p(str) str2pfx_raw((str), &pfx)
#define BPT_insert bgpstream_patricia_tree_insert
#define BPT_search_exact bgpstream_patricia_tree_search_exact
#define BPT_get_pfx_overlap_info bgpstream_patricia_tree_get_pfx_overlap_info
Expand Down Expand Up @@ -168,6 +217,66 @@ static int test_patricia()
}
bgpstream_patricia_tree_destroy(pt);

/* Default route */
pt = bgpstream_patricia_tree_create(NULL);
res = bgpstream_patricia_tree_result_set_create();
count4 = 0;
INSERT(4, "10.0.0.0/8", ++count4);
INSERT(4, "10.1.2.3/32", ++count4);
INSERT(4, "0.0.0.0/0", ++count4);
INSERT(4, "192.172.226.78/32", ++count4);

CHECK("Patricia Tree v4 default route - non-default case",
(node = BPT_search_exact(pt, s2p("10.1.2.3/32"))) != NULL &&
BPT_get_mincovering_pfx(pt, node, res) == 0 &&
bgpstream_patricia_tree_result_set_count(res) == 1 &&
(node = bgpstream_patricia_tree_result_set_next(res)) != NULL &&
(pfxp = BPT_get_pfx(node)) != NULL &&
bgpstream_pfx_equal(pfxp, s2p("10.0.0.0/8")) != 0);

CHECK("Patricia Tree v4 default route - default case",
(node = BPT_search_exact(pt, s2p("192.172.226.78/32"))) != NULL &&
BPT_get_mincovering_pfx(pt, node, res) == 0 &&
bgpstream_patricia_tree_result_set_count(res) == 1 &&
(node = bgpstream_patricia_tree_result_set_next(res)) != NULL &&
(pfxp = BPT_get_pfx(node)) != NULL &&
bgpstream_pfx_equal(pfxp, s2p("0.0.0.0/0")) != 0);
bgpstream_patricia_tree_destroy(pt);
bgpstream_patricia_tree_result_set_destroy(&res);

/* Incorrectly masked prefixes */
pt = bgpstream_patricia_tree_create(NULL);
res = bgpstream_patricia_tree_result_set_create();
count4 = 0;

// simple case: we expect the parent of 10.1.2.3/32 to be 10.1.0.0/16
INSERT(4, "10.1.2.3/16", ++count4); // should be masked off during insertion
INSERT(4, "10.1.2.3/32", ++count4);
// insert a node so that a glue node is created at the root
INSERT(4, "192.172.226.77/32", ++count4);
// insert our incorrectly masked "default" route, it should replace the root glue node
INSERT(4, "192.172.226.78/0", ++count4);
INSERT(4, "192.172.226.78/32", ++count4);

CHECK("Patricia Tree v4 - unmasked prefixes",
(node = BPT_search_exact(pt, s2p("10.1.2.3/32"))) != NULL &&
BPT_get_mincovering_pfx(pt, node, res) == 0 &&
bgpstream_patricia_tree_result_set_count(res) == 1 &&
(node = bgpstream_patricia_tree_result_set_next(res)) != NULL &&
(pfxp = BPT_get_pfx(node)) != NULL &&
bgpstream_pfx_equal(pfxp, s2p("10.1.0.0/16")) != 0);

CHECK("Patricia Tree v4 - unmasked prefixes; replace glue",
(node = BPT_search_exact(pt, s2p("192.172.226.78/32"))) != NULL &&
BPT_get_mincovering_pfx(pt, node, res) == 0 &&
bgpstream_patricia_tree_result_set_count(res) == 1 &&
(node = bgpstream_patricia_tree_result_set_next(res)) != NULL &&
(pfxp = BPT_get_pfx(node)) != NULL &&
bgpstream_pfx_equal(pfxp, s2p("0.0.0.0/0")) != 0);

bgpstream_patricia_tree_destroy(pt);
bgpstream_patricia_tree_result_set_destroy(&res);

return 0;
}

Expand Down