xt_ipp2p: move the protocol-specific code out into separate functions

Signed-off-by: Jeremy Sowden <jeremy@azazel.net>

diff --git a/extensions/xt_ipp2p.c b/extensions/xt_ipp2p.c
index 4e0fbb675c76323dec53eee4fcfd524cd22aee82..0ed4412aaeec9c61c4b85fee89869faa8345af88 100644 (file)
--- a/extensions/xt_ipp2p.c
+++ b/extensions/xt_ipp2p.c
@@ -807,15 +807,97 @@ static const struct {
        {0},
 };
 
+static bool
+ipp2p_mt_tcp(const struct ipt_p2p_info *info, const struct tcphdr *tcph,
+             const unsigned char *haystack, unsigned int hlen,
+             const struct iphdr *ip)
+{
+       size_t tcph_len = tcph->doff * 4;
+       bool p2p_result = false;
+       int i = 0;
+
+       if (tcph->fin) return 0;  /* if FIN bit is set bail out */
+       if (tcph->syn) return 0;  /* if SYN bit is set bail out */
+       if (tcph->rst) return 0;  /* if RST bit is set bail out */
+
+       if (hlen < tcph_len) {
+               if (info->debug)
+                       pr_info("TCP header indicated packet larger than it is\n");
+               return 0;
+       }
+       if (hlen == tcph_len)
+               return 0;
+
+       haystack += tcph_len;
+       hlen     -= tcph_len;
+
+       while (matchlist[i].command) {
+               if ((info->cmd & matchlist[i].command) == matchlist[i].command &&
+                   hlen > matchlist[i].packet_len)
+               {
+                       p2p_result = matchlist[i].function_name(haystack, hlen);
+                       if (p2p_result) {
+                               if (info->debug)
+                                       printk("IPP2P.debug:TCP-match: %d from: %pI4:%hu to: %pI4:%hu Length: %d\n",
+                                              p2p_result, &ip->saddr,
+                                              ntohs(tcph->source),
+                                              &ip->daddr,
+                                              ntohs(tcph->dest), hlen);
+                               return p2p_result;
+                       }
+               }
+               i++;
+       }
+       return p2p_result;
+}
+
+static bool
+ipp2p_mt_udp(const struct ipt_p2p_info *info, const struct udphdr *udph,
+             const unsigned char *haystack, unsigned int hlen,
+             const struct iphdr *ip)
+{
+       size_t udph_len = sizeof(*udph);
+       bool p2p_result = false;
+       int i = 0;
+
+       if (hlen < udph_len) {
+               if (info->debug)
+                       pr_info("UDP header indicated packet larger than it is\n");
+               return 0;
+       }
+       if (hlen == udph_len)
+               return 0;
+
+       haystack += udph_len;
+       hlen     -= udph_len;
+
+       while (udp_list[i].command) {
+               if ((info->cmd & udp_list[i].command) == udp_list[i].command &&
+                   hlen > udp_list[i].packet_len)
+               {
+                       p2p_result = udp_list[i].function_name(haystack, hlen);
+                       if (p2p_result) {
+                               if (info->debug)
+                                       printk("IPP2P.debug:UDP-match: %d from: %pI4:%hu to: %pI4:%hu Length: %d\n",
+                                              p2p_result, &ip->saddr,
+                                              ntohs(udph->source),
+                                              &ip->daddr,
+                                              ntohs(udph->dest), hlen);
+                               return p2p_result;
+                       }
+               }
+               i++;
+       }
+       return p2p_result;
+}
+
 static bool
 ipp2p_mt(const struct sk_buff *skb, struct xt_action_param *par)
 {
        const struct ipt_p2p_info *info = par->matchinfo;
-       const unsigned char  *haystack;
        const struct iphdr *ip = ip_hdr(skb);
-       bool p2p_result = false;
-       int i = 0;
-       unsigned int hlen = ntohs(ip->tot_len) - ip_hdrlen(skb);        /* hlen = packet-data length */
+       const unsigned char *haystack;  /* packet data */
+       unsigned int hlen;              /* packet data length */
 
        /* must not be a fragment */
        if (par->fragoff != 0) {
@@ -831,84 +913,23 @@ ipp2p_mt(const struct sk_buff *skb, struct xt_action_param *par)
                return 0;
        }
 
-       haystack = skb_network_header(skb) + ip_hdrlen(skb);
+       haystack = skb_transport_header(skb);
+       hlen     = ntohs(ip->tot_len) - skb_transport_offset(skb);
 
        switch (ip->protocol) {
        case IPPROTO_TCP:       /* what to do with a TCP packet */
        {
-               const struct tcphdr *tcph = (const void *)ip + ip_hdrlen(skb);
-
-               if (tcph->fin) return 0;  /* if FIN bit is set bail out */
-               if (tcph->syn) return 0;  /* if SYN bit is set bail out */
-               if (tcph->rst) return 0;  /* if RST bit is set bail out */
-
-               if (tcph->doff * 4 > hlen) {
-                       if (info->debug)
-                               pr_info("TCP header indicated packet larger than it is\n");
-                       return 0;
-               }
-               if (tcph->doff * 4 == hlen)
-                       return 0;
+               const struct tcphdr *tcph = tcp_hdr(skb);
 
-               haystack += tcph->doff * 4; /* get TCP-Header-Size */
-               hlen     -= tcph->doff * 4;
-
-               while (matchlist[i].command) {
-                       if ((info->cmd & matchlist[i].command) == matchlist[i].command &&
-                           hlen > matchlist[i].packet_len)
-                       {
-                               p2p_result = matchlist[i].function_name(haystack, hlen);
-                               if (p2p_result) {
-                                       if (info->debug)
-                                               printk("IPP2P.debug:TCP-match: %d from: %pI4:%hu to: %pI4:%hu Length: %d\n",
-                                                      p2p_result, &ip->saddr,
-                                                      ntohs(tcph->source),
-                                                      &ip->daddr,
-                                                      ntohs(tcph->dest), hlen);
-                                       return p2p_result;
-                               }
-                       }
-                       i++;
-               }
-               return p2p_result;
+               return ipp2p_mt_tcp(info, tcph, haystack, hlen, ip);
        }
-
-       case IPPROTO_UDP:       /* what to do with an UDP packet */
+       case IPPROTO_UDP:       /* what to do with a UDP packet */
        case IPPROTO_UDPLITE:
        {
-               const struct udphdr *udph = (const void *)ip + ip_hdrlen(skb);
+               const struct udphdr *udph = udp_hdr(skb);
 
-               if (sizeof(*udph) > hlen) {
-                       if (info->debug)
-                               pr_info("UDP header indicated packet larger than it is\n");
-                       return 0;
-               }
-               if (sizeof(*udph) == hlen)
-                       return 0;
-
-               haystack += sizeof(*udph);
-               hlen     -= sizeof(*udph);
-
-               while (udp_list[i].command) {
-                       if ((info->cmd & udp_list[i].command) == udp_list[i].command &&
-                           hlen > udp_list[i].packet_len)
-                       {
-                               p2p_result = udp_list[i].function_name(haystack, hlen);
-                               if (p2p_result) {
-                                       if (info->debug)
-                                               printk("IPP2P.debug:UDP-match: %d from: %pI4:%hu to: %pI4:%hu Length: %d\n",
-                                                      p2p_result, &ip->saddr,
-                                                      ntohs(udph->source),
-                                                      &ip->daddr,
-                                                      ntohs(udph->dest), hlen);
-                                       return p2p_result;
-                               }
-                       }
-                       i++;
-               }
-               return p2p_result;
+               return ipp2p_mt_udp(info, udph, haystack, hlen, ip);
        }
-
        default:
                return 0;
        }