From: Craig Gallek Date: Mon, 18 Sep 2017 19:30:56 +0000 (-0400) Subject: bpf: Add uniqueness invariant to trivial lpm test implementation X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=bae30468dfc1522464f16051addd7bc7da6da75a;p=openwrt%2Fstaging%2Fblogic.git bpf: Add uniqueness invariant to trivial lpm test implementation The 'trivial' lpm implementation in this test allows equivalent nodes to be added (that is, nodes consisting of the same prefix and prefix length). For lookup operations, this is fine because insertion happens at the head of the (singly linked) list and the first, best match is returned. In order to support deletion, the tlpm data structue must first enforce uniqueness. This change modifies the insertion algorithm to search for equivalent nodes and remove them. Note: the BPF_MAP_TYPE_LPM_TRIE already has a uniqueness invariant that is implemented as node replacement. Signed-off-by: Craig Gallek Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- diff --git a/tools/testing/selftests/bpf/test_lpm_map.c b/tools/testing/selftests/bpf/test_lpm_map.c index e97565243d59..a5ed7c4f1819 100644 --- a/tools/testing/selftests/bpf/test_lpm_map.c +++ b/tools/testing/selftests/bpf/test_lpm_map.c @@ -31,6 +31,10 @@ struct tlpm_node { uint8_t key[]; }; +static struct tlpm_node *tlpm_match(struct tlpm_node *list, + const uint8_t *key, + size_t n_bits); + static struct tlpm_node *tlpm_add(struct tlpm_node *list, const uint8_t *key, size_t n_bits) @@ -38,9 +42,17 @@ static struct tlpm_node *tlpm_add(struct tlpm_node *list, struct tlpm_node *node; size_t n; + n = (n_bits + 7) / 8; + + /* 'overwrite' an equivalent entry if one already exists */ + node = tlpm_match(list, key, n_bits); + if (node && node->n_bits == n_bits) { + memcpy(node->key, key, n); + return list; + } + /* add new entry with @key/@n_bits to @list and return new head */ - n = (n_bits + 7) / 8; node = malloc(sizeof(*node) + n); assert(node);