BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.protocol)), /* A <- IP protocol */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, IPPROTO_UDP, 1, 0), /* IP protocol == UDP ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
+ BPF_STMT(BPF_LD + BPF_B + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags */
+ BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x20), /* A <- A & 0x20 (More Fragments bit) */
+ BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
+ BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, ip.frag_off)), /* A <- Flags + Fragment offset */
- BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff), /* A <- A & 0x1fff */
+ BPF_STMT(BPF_ALU + BPF_AND + BPF_K, 0x1fff), /* A <- A & 0x1fff (Fragment offset) */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, udp.dest)), /* A <- UDP destination port */