lb.util — org.clojars.pgdad/clj-ebpf-lb 0.9.0

Utility functions for IP address conversion, CIDR parsing, and binary encoding.

bytes->ip clj

(bytes->ip b)

Convert 4-byte array to IP u32.

cidr->string clj

(cidr->string {:keys [ip prefix-len]})

Convert {:ip <u32> :prefix-len <int>} back to CIDR string.

decode-conntrack-key clj

(decode-conntrack-key b)

Decode connection tracking key from byte array.

decode-conntrack-value clj

(decode-conntrack-value b)

Decode connection tracking value from byte array (64 bytes).

decode-listen-key clj

(decode-listen-key b)

Decode listen map key from byte array.

decode-lpm-key clj

(decode-lpm-key b)

Decode LPM trie key from byte array.

decode-route-value clj

(decode-route-value b)

Decode route value from byte array.

decode-sni-key clj

(decode-sni-key b)

Decode SNI map key from byte array.

decode-stats-event clj

(decode-stats-event b)

Decode stats event from ring buffer.

decode-weighted-route-value clj

(decode-weighted-route-value b)

Decode weighted route value from byte array (72 bytes). Returns {:target-count :flags :targets} where targets is a vector of {:ip :port :cumulative-weight} maps.

encode-conntrack-key clj

(encode-conntrack-key {:keys [src-ip dst-ip src-port dst-port protocol]})

Encode connection tracking 5-tuple key. {src_ip (4) + dst_ip (4) + src_port (2) + dst_port (2) + protocol (1) + padding (3)} Total: 16 bytes (aligned). XDP stores packet values (network byte order) directly, so we use big-endian to match packet byte layout.

encode-conntrack-value clj

(encode-conntrack-value {:keys [orig-dst-ip orig-dst-port nat-dst-ip
                                nat-dst-port created-ns last-seen packets-fwd
                                packets-rev bytes-fwd bytes-rev]})

Encode connection tracking value. {orig_dst_ip (4) + orig_dst_port (2) + padding (2) + nat_dst_ip (4) + nat_dst_port (2) + padding (2) + created_ns (8) + last_seen_ns (8) + packets_fwd (8) + packets_rev (8) + bytes_fwd (8) + bytes_rev (8)} Total: 64 bytes. IPs and ports in network byte order (from packet), counters in native order.

encode-listen-key clj

(encode-listen-key ifindex port)

Encode listen map key: {ifindex (4 bytes) + port (2 bytes) + padding (2 bytes)}. Total: 8 bytes (aligned). Uses native byte order for ifindex, but BIG_ENDIAN for port to match raw packet bytes that XDP loads with ldx :h.

encode-lpm-key clj

(encode-lpm-key prefix-len ip-u32)

Encode LPM trie key: {prefix_len (4 bytes) + ip (4 bytes)}. Total: 8 bytes.

encode-route-value clj

(encode-route-value target-ip target-port flags)

Encode route value: {target_ip (4 bytes) + target_port (2 bytes) + flags (2 bytes)}. Total: 8 bytes. IP and port are stored in NETWORK byte order (big-endian) because XDP writes them directly to packet headers which are in network byte order. Flags remain in native order since they're only used internally.

encode-sni-key clj

(encode-sni-key hostname-hash)

Encode SNI map key from hostname hash. Key: hostname_hash (8 bytes) = 8 bytes total. Uses native byte order for efficient lookup.

encode-stats-event clj

(encode-stats-event {:keys [event-type timestamp src-ip dst-ip src-port dst-port
                            target-ip target-port packets-fwd bytes-fwd
                            packets-rev bytes-rev]})

Encode a stats event for ring buffer. {event_type (1) + padding (3) + timestamp (8) + src_ip (4) + dst_ip (4) + src_port (2) + dst_port (2) + target_ip (4) + target_port (2) + padding (2) + packets_fwd (8) + bytes_fwd (8) + packets_rev (8) + bytes_rev (8)} Total: 64 bytes.

encode-weighted-route-value clj

(encode-weighted-route-value target-group)

(encode-weighted-route-value target-group flags)

Encode weighted route value for BPF map. target-group is a TargetGroup record with :targets and :cumulative-weights. flags is optional (default 0).

Format (max 72 bytes):

• Header (8 bytes): target_count(1) + reserved(3) + flags(2) + reserved(2)
• Per target (8 bytes each): ip(4) + port(2) + cumulative_weight(2)

IP and port are stored in network byte order for direct packet writes.

ETH-HLEN clj

ETH-P-ARP clj

ETH-P-IP clj

ETH-P-IPV6 clj

FLAG-SESSION-PERSISTENCE clj

fnv1a-64 clj

(fnv1a-64 data)

Compute FNV-1a 64-bit hash of a byte array. This is a fast, non-cryptographic hash suitable for hash table lookups.

FNV1A-64-OFFSET-BASIS clj

FNV1A-64-PRIME clj

get-interface-index clj

(get-interface-index iface-name)

Get interface index by name using /sys/class/net. Returns nil if interface not found.

hostname->hash clj

(hostname->hash hostname)

Hash a hostname for SNI map lookup using FNV-1a 64-bit. Hostname is lowercased before hashing for case-insensitive matching.

ip->bytes clj

(ip->bytes ip-u32)

Convert IP u32 to byte array (4 bytes, big-endian).

IP-HLEN-MIN clj

ip-in-cidr? clj

(ip-in-cidr? ip-u32 {:keys [ip prefix-len]})

Check if an IP address (u32) falls within a CIDR range.

ip-string->u32 clj

(ip-string->u32 ip-str)

Convert dotted-decimal IP string to network byte order u32. Example: "192.168.1.1" => 0xC0A80101 (3232235777)

IPPROTO-ICMP clj

IPPROTO-TCP clj

IPPROTO-UDP clj

is-ip-string? clj

(is-ip-string? s)

Check if a string looks like an IPv4 address.

list-interfaces clj

(list-interfaces)

List all network interface names.

parse-cidr clj

(parse-cidr cidr-str)

Parse CIDR notation string to {:ip <u32> :prefix-len <int>}. Supports both CIDR (e.g., "192.168.1.0/24") and single IP (e.g., "192.168.1.1"). Single IPs are treated as /32.

port->u16 clj

(port->u16 port)

Convert port to unsigned 16-bit value.

port-valid? clj

(port-valid? port)

Check if port number is valid (1-65535).

resolve-hostname clj

(resolve-hostname hostname)

Resolve hostname to IP address (u32). Returns nil if resolution fails.

resolve-hostname-all clj

(resolve-hostname-all hostname)

Resolve hostname to ALL A records (not just first). Returns vector of u32 IPs, or nil if resolution fails.

This is useful for DNS-based load balancing where a hostname may resolve to multiple backend IPs.

resolve-to-ip clj

(resolve-to-ip source-spec)

Resolve a source specification to IP. Accepts: IP string, CIDR string, or hostname. Returns {:ip <u32> :prefix-len <int>} or nil on failure.

SNI-KEY-SIZE clj

TC-ACT-OK clj

TC-ACT-REDIRECT clj

TC-ACT-SHOT clj

TCP-HLEN-MIN clj

u32->ip-string clj

(u32->ip-string n)

Convert network byte order u32 to dotted-decimal IP string. Example: 0xC0A80101 => "192.168.1.1"

UDP-HLEN clj

WEIGHTED-ROUTE-HEADER-SIZE clj

WEIGHTED-ROUTE-MAX-SIZE clj

WEIGHTED-ROUTE-MAX-TARGETS clj

WEIGHTED-ROUTE-TARGET-SIZE clj

weighted-route-value-size clj

(weighted-route-value-size)

Return the fixed size of weighted route values (72 bytes). All weighted routes use the same size for BPF map compatibility.

XDP-ABORTED clj

XDP-DROP clj

XDP-PASS clj

XDP-REDIRECT clj

XDP-TX clj