[NETFILTER]: FTP helper: search optimization

Instead of skipping search entries for the wrong direction simply index
them by direction.

Based on patch by Pablo Neira <pablo@netfilter.org>

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 43 insertions, 34 deletions

diff --git a/net/ipv4/netfilter/ip_conntrack_ftp.c b/net/ipv4/netfilter/ip_conntrack_ftp.c
index 3e542bf28a9d..4dcf526c3944 100644
--- a/net/ipv4/netfilter/ip_conntrack_ftp.c
+++ b/net/ipv4/netfilter/ip_conntrack_ftp.c
@@ -56,37 +56,48 @@ static int try_eprt(const char *, size_t, u_int32_t [], char);
 static int try_epsv_response(const char *, size_t, u_int32_t [], char);
 
 static const struct ftp_search {
-        enum ip_conntrack_dir dir;
         const char *pattern;
         size_t plen;
         char skip;
         char term;
         enum ip_ct_ftp_type ftptype;
         int (*getnum)(const char *, size_t, u_int32_t[], char);
-} search[] = {
-        {
-                IP_CT_DIR_ORIGINAL,
-                "PORT", sizeof("PORT") - 1, ' ', '\r',
-                IP_CT_FTP_PORT,
-                try_rfc959,
+} search[IP_CT_DIR_MAX][2] = {
+        [IP_CT_DIR_ORIGINAL] = {
+                {
+                        .pattern        =  "PORT",
+                        .plen           = sizeof("PORT") - 1,
+                        .skip           = ' ',
+                        .term           = '\r',
+                        .ftptype        = IP_CT_FTP_PORT,
+                        .getnum         = try_rfc959,
+                },
+                {
+                        .pattern        = "EPRT",
+                        .plen           = sizeof("EPRT") - 1,
+                        .skip           = ' ',
+                        .term           = '\r',
+                        .ftptype        = IP_CT_FTP_EPRT,
+                        .getnum         = try_eprt,
+                },
         },
-        {
-                IP_CT_DIR_REPLY,
-                "227 ", sizeof("227 ") - 1, '(', ')',
-                IP_CT_FTP_PASV,
-                try_rfc959,
-        },
-        {
-                IP_CT_DIR_ORIGINAL,
-                "EPRT", sizeof("EPRT") - 1, ' ', '\r',
-                IP_CT_FTP_EPRT,
-                try_eprt,
-        },
-        {
-                IP_CT_DIR_REPLY,
-                "229 ", sizeof("229 ") - 1, '(', ')',
-                IP_CT_FTP_EPSV,
-                try_epsv_response,
+        [IP_CT_DIR_REPLY] = {
+                {
+                        .pattern        = "227 ",
+                        .plen           = sizeof("227 ") - 1,
+                        .skip           = '(',
+                        .term           = ')',
+                        .ftptype        = IP_CT_FTP_PASV,
+                        .getnum         = try_rfc959,
+                },
+                {
+                        .pattern        = "229 ",
+                        .plen           = sizeof("229 ") - 1,
+                        .skip           = '(',
+                        .term           = ')',
+                        .ftptype        = IP_CT_FTP_EPSV,
+                        .getnum         = try_epsv_response,
+                },
         },
 };
 
@@ -346,17 +357,15 @@ static int help(struct sk_buff **pskb,
         array[2] = (ntohl(ct->tuplehash[dir].tuple.src.ip) >> 8) & 0xFF;
         array[3] = ntohl(ct->tuplehash[dir].tuple.src.ip) & 0xFF;
 
-        for (i = 0; i < ARRAY_SIZE(search); i++) {
-                if (search[i].dir != dir) continue;
-
+        for (i = 0; i < ARRAY_SIZE(search[dir]); i++) {
                 found = find_pattern(fb_ptr, (*pskb)->len - dataoff,
-                                     search[i].pattern,
-                                     search[i].plen,
-                                     search[i].skip,
-                                     search[i].term,
+                                     search[dir][i].pattern,
+                                     search[dir][i].plen,
+                                     search[dir][i].skip,
+                                     search[dir][i].term,
                                      &matchoff, &matchlen,
                                      array,
-                                     search[i].getnum);
+                                     search[dir][i].getnum);
                 if (found) break;
         }
         if (found == -1) {
@@ -366,7 +375,7 @@ static int help(struct sk_buff **pskb,
                    this case. */
                 if (net_ratelimit())
                         printk("conntrack_ftp: partial %s %u+%u\n",
-                               search[i].pattern,
+                               search[dir][i].pattern,
                                ntohl(th->seq), datalen);
                 ret = NF_DROP;
                 goto out;
@@ -426,7 +435,7 @@ static int help(struct sk_buff **pskb,
         /* Now, NAT might want to mangle the packet, and register the
          * (possibly changed) expectation itself. */
         if (ip_nat_ftp_hook)
-                ret = ip_nat_ftp_hook(pskb, ctinfo, search[i].ftptype,
+                ret = ip_nat_ftp_hook(pskb, ctinfo, search[dir][i].ftptype,
                                       matchoff, matchlen, exp, &seq);
         else {
                 /* Can't expect this?  Best to drop packet now. */