Commit b95a5c4d authored by Daniel Mack's avatar Daniel Mack Committed by David S. Miller

bpf: add a longest prefix match trie map implementation

This trie implements a longest prefix match algorithm that can be used
to match IP addresses to a stored set of ranges.

Internally, data is stored in an unbalanced trie of nodes that has a
maximum height of n, where n is the prefixlen the trie was created

Tries may be created with prefix lengths that are multiples of 8, in
the range from 8 to 2048. The key used for lookup and update operations
is a struct bpf_lpm_trie_key, and the value is a uint64_t.

The code carries more information about the internal implementation.
Signed-off-by: default avatarDaniel Mack <>
Reviewed-by: default avatarDavid Herrmann <>
Acked-by: default avatarAlexei Starovoitov <>
Signed-off-by: default avatarDavid S. Miller <>
parent 10eeb5e6
......@@ -63,6 +63,12 @@ struct bpf_insn {
__s32 imm; /* signed immediate constant */
/* Key of an a BPF_MAP_TYPE_LPM_TRIE entry */
struct bpf_lpm_trie_key {
__u32 prefixlen; /* up to 32 for AF_INET, 128 for AF_INET6 */
__u8 data[0]; /* Arbitrary size */
/* BPF syscall commands, see bpf(2) man-page for details. */
enum bpf_cmd {
......@@ -89,6 +95,7 @@ enum bpf_map_type {
enum bpf_prog_type {
obj-y := core.o
obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o
obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o
obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o
obj-$(CONFIG_BPF_SYSCALL) += stackmap.o
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