#ifdef __linux__
#define _BSD_SOURCE
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifndef USE_NETLIB
#include <net/ethernet.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#else
#include <netlib.h>
#endif
#include "pktlib.h"
#include "pktbuf.h"
pktbuf_t pktbuf_make_udp(pktbuf_t pktbuf, struct header_param *param)
{
 struct udphdr *udphdr;
 int hdrsize, paysize;
 hdrsize = sizeof(*udphdr);
 paysize = pktbuf_get_size(pktbuf);
 udphdr = (struct udphdr *)pktbuf_add_header(pktbuf, hdrsize);
 memset(udphdr, 0, hdrsize);
 udphdr->uh_sport = htons(param->udp.src_port);
 udphdr->uh_dport = htons(param->udp.dst_port);
 udphdr->uh_ulen = htons(hdrsize + paysize);
 return pktbuf;
}
pktbuf_t pktbuf_make_ip(pktbuf_t pktbuf, struct header_param *param)
{
 struct ip *iphdr;
 int hdrsize, paysize;
 hdrsize = sizeof(struct ip);
 paysize = pktbuf_get_size(pktbuf);
 iphdr = (struct ip *)pktbuf_add_header(pktbuf, hdrsize);
 memset(iphdr, 0, hdrsize);
 iphdr->ip_v = 4;
 iphdr->ip_hl = hdrsize>> 2;
 iphdr->ip_len = htons(hdrsize + paysize);
 iphdr->ip_id = htons(param->ip.id);
 iphdr->ip_ttl = param->ip.ttl;
 iphdr->ip_p = param->ip.protocol;
 iphdr->ip_src.s_addr = htonl(param->ip.src_ipaddr);
 iphdr->ip_dst.s_addr = htonl(param->ip.dst_ipaddr);
 return pktbuf;
}
struct vlantag {
 uint16_t type;
 uint16_t tag;
} vlantag;
pktbuf_t pktbuf_insert_vlantag(pktbuf_t pktbuf, int vid)
{
 struct ether_header ether_header;
 struct ether_header *ehdr;
 struct vlantag *vtag;
 if (!vid)
 return pktbuf;
 memcpy(&ether_header, pktbuf_get_header(pktbuf), ETHER_HDR_LEN);
 ehdr = (struct ether_header *)pktbuf_add_header(pktbuf, sizeof(*vtag));
 vtag = (struct vlantag *)&ehdr->ether_type;
 memcpy(ehdr, &ether_header, ETHER_HDR_LEN);
 vtag->type = htons(ETHERTYPE_VLAN);
 vtag->tag = htons(vid & 0x0FFF);
 return pktbuf;
}
pktbuf_t pktbuf_delete_vlantag(pktbuf_t pktbuf, int *vid)
{
 struct ether_header ether_header;
 struct ether_header *ehdr;
 struct vlantag *vtag;
 ehdr = (struct ether_header *)pktbuf_get_header(pktbuf);
 if (ntohs(ehdr->ether_type) != ETHERTYPE_VLAN) {
 if (vid) *vid = 0;
 return pktbuf;
 }
 memcpy(&ether_header, ehdr, ETHER_HDR_LEN);
 vtag = (struct vlantag *)&ehdr->ether_type;
 if (vid) *vid = ntohs(vtag->tag) & 0x0FFF;
 ehdr = (struct ether_header *)pktbuf_delete_header(pktbuf, sizeof(*vtag));
 ether_header.ether_type = ehdr->ether_type;
 memcpy(ehdr, &ether_header, ETHER_HDR_LEN);
 return pktbuf;
}
pktbuf_t pktbuf_make_ethernet(pktbuf_t pktbuf, struct header_param *param)
{
 struct ether_header *ehdr;
 ehdr = (struct ether_header *)pktbuf_add_header(pktbuf, ETHER_HDR_LEN);
 memcpy(ehdr->ether_dhost, param->ethernet.dst_macaddr, ETHER_ADDR_LEN);
 memcpy(ehdr->ether_shost, param->ethernet.src_macaddr, ETHER_ADDR_LEN);
 ehdr->ether_type = htons(param->ethernet.type);
 pktbuf = pktbuf_insert_vlantag(pktbuf, param->ethernet.vid);
 return pktbuf;
}
int pktbuf_analyze_udp(pktbuf_t pktbuf, struct header_param *param)
{
 struct udphdr *udphdr;
 int r = 0;
 if (pktbuf_get_size(pktbuf) < sizeof(*udphdr)) return r; udphdr = (struct udphdr *)pktbuf_get_header(pktbuf); if (pktbuf_get_size(pktbuf) < ntohs(udphdr->uh_ulen))
 return r;
 param->udp.header_size = sizeof(*udphdr);
 param->udp.src_port = ntohs(udphdr->uh_sport);
 param->udp.dst_port = ntohs(udphdr->uh_dport);
 r++;
 return r;
}
int pktbuf_analyze_ip(pktbuf_t pktbuf, struct header_param *param)
{
 struct ip *iphdr;
 int r = 0, hdrsize;
 if (pktbuf_get_size(pktbuf) < sizeof(struct ip)) return r; iphdr = (struct ip *)pktbuf_get_header(pktbuf); if (iphdr->ip_v != 4)
 return r;
 hdrsize = iphdr->ip_hl << 2; if (hdrsize < sizeof(struct ip)) return r; if (pktbuf_get_size(pktbuf) < hdrsize) return r; if (pktbuf_get_size(pktbuf) < ntohs(iphdr->ip_len))
 return r;
 param->ip.header_size = hdrsize;
 param->ip.id = ntohs(iphdr->ip_id);
 param->ip.ttl = iphdr->ip_ttl;
 param->ip.protocol = iphdr->ip_p;
 param->ip.src_ipaddr = ntohl(iphdr->ip_src.s_addr);
 param->ip.dst_ipaddr = ntohl(iphdr->ip_dst.s_addr);
 r++;
 pktbuf_delete_header(pktbuf, hdrsize);
 switch (param->ip.protocol) {
 case IPPROTO_UDP:
 r += pktbuf_analyze_udp(pktbuf, param);
 break;
 default:
 break;
 }
 pktbuf_add_header(pktbuf, hdrsize);
 return r;
}
int pktbuf_analyze_ethernet(pktbuf_t pktbuf, struct header_param *param)
{
 struct ether_header *ehdr;
 int r = 0;
 if (pktbuf_get_size(pktbuf) < ETHER_HDR_LEN) return r; ehdr = (struct ether_header *)pktbuf_get_header(pktbuf); param->ethernet.header_size = ETHER_HDR_LEN;
 memcpy(param->ethernet.dst_macaddr, ehdr->ether_dhost, ETHER_ADDR_LEN);
 memcpy(param->ethernet.src_macaddr, ehdr->ether_shost, ETHER_ADDR_LEN);
 param->ethernet.type = ntohs(ehdr->ether_type);
 r++;
 pktbuf_delete_vlantag(pktbuf, &param->ethernet.vid);
 pktbuf_delete_header(pktbuf, ETHER_HDR_LEN);
 switch (param->ethernet.type) {
 case ETHERTYPE_IP:
 r += pktbuf_analyze_ip(pktbuf, param);
 break;
 default:
 break;
 }
 pktbuf_add_header(pktbuf, ETHER_HDR_LEN);
 pktbuf_insert_vlantag(pktbuf, param->ethernet.vid);
 return r;
}
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