1 files changed, 124 insertions, 0 deletions
diff --git a/src/proxy.c b/src/proxy.c
new file mode 100644
index 0000000..b9bb04e
--- /dev/null
+++ b/src/proxy.c
@@ -0,0 +1,124 @@
+/*
+ * (C) 2006 by Pablo Neira Ayuso <pablo@netfilter.org>
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <libnfnetlink/libnfnetlink.h>
+#include <libnetfilter_conntrack/libnetfilter_conntrack.h>
+
+#if 0
+#define dprintf printf
+#else
+#define dprintf
+#endif
+
+int nlh_payload_host2network(struct nfattr *nfa, int len)
+{
+	struct nfattr *__nfa;
+
+	while (NFA_OK(nfa, len)) {
+
+		dprintf("type=%d nfalen=%d len=%d [%s]\n", 
+			nfa->nfa_type & 0x7fff,
+			nfa->nfa_len, len,
+			nfa->nfa_type & NFNL_NFA_NEST ? "NEST":"");
+
+		if (nfa->nfa_type & NFNL_NFA_NEST) {
+			if (NFA_PAYLOAD(nfa) > len)
+				return -1;
+
+			if (nlh_payload_host2network(NFA_DATA(nfa), 
+						     NFA_PAYLOAD(nfa)) == -1)
+				return -1;
+		}
+
+		__nfa = NFA_NEXT(nfa, len);
+
+		nfa->nfa_type = htons(nfa->nfa_type);
+		nfa->nfa_len  = htons(nfa->nfa_len);
+
+		nfa = __nfa; 
+	}
+	return 0;
+}
+
+int nlh_host2network(struct nlmsghdr *nlh)
+{
+	struct nfgenmsg *nfhdr = NLMSG_DATA(nlh);
+	struct nfattr *cda[CTA_MAX];
+	unsigned int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
+	unsigned int len = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
+
+	nlh->nlmsg_len   = htonl(nlh->nlmsg_len);
+	nlh->nlmsg_type  = htons(nlh->nlmsg_type);
+	nlh->nlmsg_flags = htons(nlh->nlmsg_flags);
+	nlh->nlmsg_seq   = htonl(nlh->nlmsg_seq);
+	nlh->nlmsg_pid   = htonl(nlh->nlmsg_pid);
+
+	nfhdr->res_id    = htons(nfhdr->res_id);
+
+	return nlh_payload_host2network(NFM_NFA(NLMSG_DATA(nlh)), len);
+}
+
+int nlh_payload_network2host(struct nfattr *nfa, int len)
+{
+	nfa->nfa_type = ntohs(nfa->nfa_type);
+	nfa->nfa_len  = ntohs(nfa->nfa_len);
+
+	while(NFA_OK(nfa, len)) {
+
+                dprintf("type=%d nfalen=%d len=%d [%s]\n", 
+		        nfa->nfa_type & 0x7fff, 
+		        nfa->nfa_len, len, 
+		        nfa->nfa_type & NFNL_NFA_NEST ? "NEST":"");
+
+		if (nfa->nfa_type & NFNL_NFA_NEST) {
+			if (NFA_PAYLOAD(nfa) > len)
+				return -1;
+
+			if (nlh_payload_network2host(NFA_DATA(nfa),
+						     NFA_PAYLOAD(nfa)) == -1)
+				return -1;
+		}
+
+		nfa = NFA_NEXT(nfa,len);
+
+		if (len < NFA_LENGTH(0))
+			break;
+
+		nfa->nfa_type = ntohs(nfa->nfa_type);
+		nfa->nfa_len  = ntohs(nfa->nfa_len);
+	}
+	return 0;
+}
+
+int nlh_network2host(struct nlmsghdr *nlh)
+{
+	struct nfgenmsg *nfhdr = NLMSG_DATA(nlh);
+	struct nfattr *cda[CTA_MAX];
+	unsigned int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
+	unsigned int len = ntohl(nlh->nlmsg_len) - NLMSG_ALIGN(min_len);
+
+	nlh->nlmsg_len   = ntohl(nlh->nlmsg_len);
+	nlh->nlmsg_type  = ntohs(nlh->nlmsg_type);
+	nlh->nlmsg_flags = ntohs(nlh->nlmsg_flags);
+	nlh->nlmsg_seq   = ntohl(nlh->nlmsg_seq);
+	nlh->nlmsg_pid   = ntohl(nlh->nlmsg_pid);
+
+	nfhdr->res_id    = ntohs(nfhdr->res_id);
+
+	return nlh_payload_network2host(NFM_NFA(NLMSG_DATA(nlh)), len);
+}