libnet提供的接口函数按其作用可分为四类：
* 内存管理(分配和释放)函数
* 地址解析函数
* 数据包构造函数
* 数据包发送函数

以下分别列出这些接口函数及其功能(其参数含义简单易懂，不再解释)：

★内存管理函数

单数据包内存初始化：
int libnet_init_packet(u_short packet_size, u_char **buf);

单数据包内存释放：
void libnet_destroy_packet(u_char **buf);

多数据包内存初始化：
int libnet_init_packet_arena(struct libnet_arena **arena,u_short packet_num, u_short packet_size);

访问多数据包内存中的下一个数据包：
u_char *libnet_next_packet_from_arena(struct libnet_arena **arena,u_short packet_size);

多数据包内存释放：
void libnet_destroy_packet_arena(struct libnet_arena **arena);

★ 地址解析函数

解析主机名：
u_char *libnet_host_lookup(u_long ip, u_short use_name);

解析主机名(可重入函数)：
void libnet_host_lookup_r(u_long ip, u_short use_name, u_char *buf);

域名解析：
u_long libnet_name_resolve(u_char *ip, u_short use_name);

获取接口设备IP地址：
u_long libnet_get_ipaddr(struct libnet_link_int *l,const u_char *device, const u_char *ebuf);

获取接口设备硬件地址：
struct ether_addr *libnet_get_hwaddr(struct libnet_link_int *l,const u_char *device,const u_char *ebuf);

★ 数据包构造函数

ARP协议数据包：
int libnet_build_arp(u_short hrdw, u_short prot, u_short h_len,u_short p_len, u_short op, u_char *s_ha,
u_char *s_pa, u_char *t_ha, u_char *t_pa,const u_char *payload, int payload_len,u_char *packet_buf);

DNS协议数据包：
int libnet_build_dns(u_short id, u_short flags, u_short num_q,u_short num_answ_rr, u_short num_auth_rr,
u_short num_add_rr, const u_char * payload,int payload_len, u_char *packet_buf);

以太网协议数据包：
int libnet_build_ethernet(u_char *daddr, u_char *saddr, u_short id,const u_char *payload, int payload_len,
u_char *packet_buf);

ICMP协议数据包(ICMP_ECHO / ICMP_ECHOREPLY)：
int libnet_build_icmp_echo(u_char type, u_char code, u_short id,
u_short seq, const u_char *payload,int payload_len, u_char *packet_buf);

ICMP协议数据包(ICMP_MASKREQ / ICMP_MASKREPLY)：
int libnet_build_icmp_mask(u_char type, u_char code, u_short id,
u_short seq, u_long mask,const u_char *payload, int payload_len,
u_char *packet_buf);

ICMP协议数据包(ICMP_UNREACH)：
int libnet_build_icmp_unreach(u_char type, u_char code,
u_short orig_len, u_char orig_tos,u_short orig_id, u_short orig_frag,
u_char orig_ttl, u_char orig_prot,u_long orig_saddr, u_long orig_daddr,
const u_char *payload, int payload_len,u_char *packet_buf);

ICMP协议数据包(ICMP_TIMEXCEED)：
int libnet_build_icmp_timeexceed(u_char type, u_char code,
u_short orig_len, u_char orig_tos,u_short orig_id, u_short orig_frag,
u_char orig_ttl, u_char orig_prot,u_long orig_saddr, u_long orig_daddr,
const u_char *payload, int payload_len,u_char *packet_buf);

ICMP协议数据包(ICMP_REDIRECT)：
int libnet_build_icmp_redirect(u_char type, u_char code, u_long gateway,
u_short orig_len, u_char orig_tos,u_short orig_id, u_short orig_frag,
u_char orig_ttl, u_char orig_prot,u_long orig_saddr, u_long orig_daddr,
const u_char *payload, int payload_len,u_char *packet_buf);

ICMP协议数据包(ICMP_TSTAMP / ICMP_TSTAMPREPLY)：
int libnet_build_icmp_timestamp(u_char type, u_char code, u_short id,
u_short seq, n_time otime, n_time rtime,n_time ttime, const u_char *payload,
int payload_len, u_char *packet_buf);

IGMP协议数据包：
int libnet_build_igmp(u_char type, u_char code, u_long ip,
const u_char *payload, int payload_len,u_char *packet_buf);