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Diffstat (limited to 'pfinet/linux-src/net/ipv4/ip_masq_app.c')
-rw-r--r--pfinet/linux-src/net/ipv4/ip_masq_app.c603
1 files changed, 603 insertions, 0 deletions
diff --git a/pfinet/linux-src/net/ipv4/ip_masq_app.c b/pfinet/linux-src/net/ipv4/ip_masq_app.c
new file mode 100644
index 00000000..84e059fa
--- /dev/null
+++ b/pfinet/linux-src/net/ipv4/ip_masq_app.c
@@ -0,0 +1,603 @@
+/*
+ * IP_MASQ_APP application masquerading module
+ *
+ *
+ * $Id: ip_masq_app.c,v 1.16 1998/08/29 23:51:14 davem Exp $
+ *
+ * Author: Juan Jose Ciarlante, <jjciarla@raiz.uncu.edu.ar>
+ *
+ *
+ * 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.
+ *
+ * Fixes:
+ * JJC : Implemented also input pkt hook
+ * Miquel van Smoorenburg : Copy more stuff when resizing skb
+ *
+ *
+ * FIXME:
+ * - ip_masq_skb_replace(): use same skb if space available.
+ *
+ */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <linux/in.h>
+#include <linux/ip.h>
+#include <linux/init.h>
+#include <net/protocol.h>
+#include <net/tcp.h>
+#include <net/udp.h>
+#include <asm/system.h>
+#include <linux/stat.h>
+#include <linux/proc_fs.h>
+#include <net/ip_masq.h>
+
+#define IP_MASQ_APP_TAB_SIZE 16 /* must be power of 2 */
+
+#define IP_MASQ_APP_HASH(proto, port) ((port^proto) & (IP_MASQ_APP_TAB_SIZE-1))
+#define IP_MASQ_APP_TYPE(proto, port) ( proto<<16 | port )
+#define IP_MASQ_APP_PORT(type) ( type & 0xffff )
+#define IP_MASQ_APP_PROTO(type) ( (type>>16) & 0x00ff )
+
+
+EXPORT_SYMBOL(register_ip_masq_app);
+EXPORT_SYMBOL(unregister_ip_masq_app);
+EXPORT_SYMBOL(ip_masq_skb_replace);
+
+/*
+ * will hold masq app. hashed list heads
+ */
+
+struct ip_masq_app *ip_masq_app_base[IP_MASQ_APP_TAB_SIZE];
+
+/*
+ * ip_masq_app registration routine
+ * port: host byte order.
+ */
+
+int register_ip_masq_app(struct ip_masq_app *mapp, unsigned short proto, __u16 port)
+{
+ unsigned long flags;
+ unsigned hash;
+ if (!mapp) {
+ IP_MASQ_ERR("register_ip_masq_app(): NULL arg\n");
+ return -EINVAL;
+ }
+ mapp->type = IP_MASQ_APP_TYPE(proto, port);
+ mapp->n_attach = 0;
+ hash = IP_MASQ_APP_HASH(proto, port);
+
+ save_flags(flags);
+ cli();
+ mapp->next = ip_masq_app_base[hash];
+ ip_masq_app_base[hash] = mapp;
+ restore_flags(flags);
+
+ return 0;
+}
+
+/*
+ * ip_masq_app unreg. routine.
+ */
+
+int unregister_ip_masq_app(struct ip_masq_app *mapp)
+{
+ struct ip_masq_app **mapp_p;
+ unsigned hash;
+ unsigned long flags;
+ if (!mapp) {
+ IP_MASQ_ERR("unregister_ip_masq_app(): NULL arg\n");
+ return -EINVAL;
+ }
+ /*
+ * only allow unregistration if it has no attachments
+ */
+ if (mapp->n_attach) {
+ IP_MASQ_ERR("unregister_ip_masq_app(): has %d attachments. failed\n",
+ mapp->n_attach);
+ return -EINVAL;
+ }
+ hash = IP_MASQ_APP_HASH(IP_MASQ_APP_PROTO(mapp->type), IP_MASQ_APP_PORT(mapp->type));
+
+ save_flags(flags);
+ cli();
+ for (mapp_p = &ip_masq_app_base[hash]; *mapp_p ; mapp_p = &(*mapp_p)->next)
+ if (mapp == (*mapp_p)) {
+ *mapp_p = mapp->next;
+ restore_flags(flags);
+ return 0;
+ }
+
+ restore_flags(flags);
+ IP_MASQ_ERR("unregister_ip_masq_app(proto=%s,port=%u): not hashed!\n",
+ masq_proto_name(IP_MASQ_APP_PROTO(mapp->type)), IP_MASQ_APP_PORT(mapp->type));
+ return -EINVAL;
+}
+
+/*
+ * get ip_masq_app object by its proto and port (net byte order).
+ */
+
+struct ip_masq_app * ip_masq_app_get(unsigned short proto, __u16 port)
+{
+ struct ip_masq_app *mapp;
+ unsigned hash;
+ unsigned type;
+
+ port = ntohs(port);
+ type = IP_MASQ_APP_TYPE(proto,port);
+ hash = IP_MASQ_APP_HASH(proto,port);
+ for(mapp = ip_masq_app_base[hash]; mapp ; mapp = mapp->next) {
+ if (type == mapp->type) return mapp;
+ }
+ return NULL;
+}
+
+/*
+ * ip_masq_app object binding related funcs.
+ */
+
+/*
+ * change ip_masq_app object's number of bindings
+ */
+
+static __inline__ int ip_masq_app_bind_chg(struct ip_masq_app *mapp, int delta)
+{
+ unsigned long flags;
+ int n_at;
+ if (!mapp) return -1;
+ save_flags(flags);
+ cli();
+ n_at = mapp->n_attach + delta;
+ if (n_at < 0) {
+ restore_flags(flags);
+ IP_MASQ_ERR("ip_masq_app: tried to set n_attach < 0 for (proto=%s,port==%d) ip_masq_app object.\n",
+ masq_proto_name(IP_MASQ_APP_PROTO(mapp->type)),
+ IP_MASQ_APP_PORT(mapp->type));
+ return -1;
+ }
+ mapp->n_attach = n_at;
+ restore_flags(flags);
+ return 0;
+}
+
+/*
+ * Bind ip_masq to its ip_masq_app based on proto and dport ALREADY
+ * set in ip_masq struct. Also calls constructor.
+ */
+
+struct ip_masq_app * ip_masq_bind_app(struct ip_masq *ms)
+{
+ struct ip_masq_app * mapp;
+
+ if (ms->protocol != IPPROTO_TCP && ms->protocol != IPPROTO_UDP)
+ return NULL;
+
+ mapp = ip_masq_app_get(ms->protocol, ms->dport);
+
+#if 0000
+/* #ifdef CONFIG_IP_MASQUERADE_IPAUTOFW */
+ if (mapp == NULL)
+ mapp = ip_masq_app_get(ms->protocol, ms->sport);
+/* #endif */
+#endif
+
+ if (mapp != NULL) {
+ /*
+ * don't allow binding if already bound
+ */
+
+ if (ms->app != NULL) {
+ IP_MASQ_ERR("ip_masq_bind_app() called for already bound object.\n");
+ return ms->app;
+ }
+
+ ms->app = mapp;
+ if (mapp->masq_init_1) mapp->masq_init_1(mapp, ms);
+ ip_masq_app_bind_chg(mapp, +1);
+ }
+ return mapp;
+}
+
+/*
+ * Unbind ms from type object and call ms destructor (does not kfree()).
+ */
+
+int ip_masq_unbind_app(struct ip_masq *ms)
+{
+ struct ip_masq_app * mapp;
+ mapp = ms->app;
+
+ if (ms->protocol != IPPROTO_TCP && ms->protocol != IPPROTO_UDP)
+ return 0;
+
+ if (mapp != NULL) {
+ if (mapp->masq_done_1) mapp->masq_done_1(mapp, ms);
+ ms->app = NULL;
+ ip_masq_app_bind_chg(mapp, -1);
+ }
+ return (mapp != NULL);
+}
+
+/*
+ * Fixes th->seq based on ip_masq_seq info.
+ */
+
+static __inline__ void masq_fix_seq(const struct ip_masq_seq *ms_seq, struct tcphdr *th)
+{
+ __u32 seq;
+
+ seq = ntohl(th->seq);
+
+ /*
+ * Adjust seq with delta-offset for all packets after
+ * the most recent resized pkt seq and with previous_delta offset
+ * for all packets before most recent resized pkt seq.
+ */
+
+ if (ms_seq->delta || ms_seq->previous_delta) {
+ if(after(seq,ms_seq->init_seq) ) {
+ th->seq = htonl(seq + ms_seq->delta);
+ IP_MASQ_DEBUG(1, "masq_fix_seq() : added delta (%d) to seq\n",ms_seq->delta);
+ } else {
+ th->seq = htonl(seq + ms_seq->previous_delta);
+ IP_MASQ_DEBUG(1, "masq_fix_seq() : added previous_delta (%d) to seq\n",ms_seq->previous_delta);
+ }
+ }
+
+
+}
+
+/*
+ * Fixes th->ack_seq based on ip_masq_seq info.
+ */
+
+static __inline__ void masq_fix_ack_seq(const struct ip_masq_seq *ms_seq, struct tcphdr *th)
+{
+ __u32 ack_seq;
+
+ ack_seq=ntohl(th->ack_seq);
+
+ /*
+ * Adjust ack_seq with delta-offset for
+ * the packets AFTER most recent resized pkt has caused a shift
+ * for packets before most recent resized pkt, use previous_delta
+ */
+
+ if (ms_seq->delta || ms_seq->previous_delta) {
+ if(after(ack_seq,ms_seq->init_seq)) {
+ th->ack_seq = htonl(ack_seq-ms_seq->delta);
+ IP_MASQ_DEBUG(1, "masq_fix_ack_seq() : subtracted delta (%d) from ack_seq\n",ms_seq->delta);
+
+ } else {
+ th->ack_seq = htonl(ack_seq-ms_seq->previous_delta);
+ IP_MASQ_DEBUG(1, "masq_fix_ack_seq() : subtracted previous_delta (%d) from ack_seq\n",ms_seq->previous_delta);
+ }
+ }
+
+}
+
+/*
+ * Updates ip_masq_seq if pkt has been resized
+ * Assumes already checked proto==IPPROTO_TCP and diff!=0.
+ */
+
+static __inline__ void masq_seq_update(struct ip_masq *ms, struct ip_masq_seq *ms_seq, unsigned mflag, __u32 seq, int diff)
+{
+ /* if (diff == 0) return; */
+
+ if ( !(ms->flags & mflag) || after(seq, ms_seq->init_seq))
+ {
+ ms_seq->previous_delta=ms_seq->delta;
+ ms_seq->delta+=diff;
+ ms_seq->init_seq=seq;
+ ms->flags |= mflag;
+ }
+}
+
+/*
+ * Output pkt hook. Will call bound ip_masq_app specific function
+ * called by ip_fw_masquerade(), assumes previously checked ms!=NULL
+ * returns (new - old) skb->len diff.
+ */
+
+int ip_masq_app_pkt_out(struct ip_masq *ms, struct sk_buff **skb_p, __u32 maddr)
+{
+ struct ip_masq_app * mapp;
+ struct iphdr *iph;
+ struct tcphdr *th;
+ int diff;
+ __u32 seq;
+
+ /*
+ * check if application masquerading is bound to
+ * this ip_masq.
+ * assumes that once an ip_masq is bound,
+ * it will not be unbound during its life.
+ */
+
+ if ( (mapp = ms->app) == NULL)
+ return 0;
+
+ iph = (*skb_p)->nh.iph;
+ th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
+
+ /*
+ * Remember seq number in case this pkt gets resized
+ */
+
+ seq = ntohl(th->seq);
+
+ /*
+ * Fix seq stuff if flagged as so.
+ */
+
+ if (ms->protocol == IPPROTO_TCP) {
+ if (ms->flags & IP_MASQ_F_OUT_SEQ)
+ masq_fix_seq(&ms->out_seq, th);
+ if (ms->flags & IP_MASQ_F_IN_SEQ)
+ masq_fix_ack_seq(&ms->in_seq, th);
+ }
+
+ /*
+ * Call private output hook function
+ */
+
+ if ( mapp->pkt_out == NULL )
+ return 0;
+
+ diff = mapp->pkt_out(mapp, ms, skb_p, maddr);
+
+ /*
+ * Update ip_masq seq stuff if len has changed.
+ */
+
+ if (diff != 0 && ms->protocol == IPPROTO_TCP)
+ masq_seq_update(ms, &ms->out_seq, IP_MASQ_F_OUT_SEQ, seq, diff);
+
+ return diff;
+}
+
+/*
+ * Input pkt hook. Will call bound ip_masq_app specific function
+ * called by ip_fw_demasquerade(), assumes previously checked ms!=NULL.
+ * returns (new - old) skb->len diff.
+ */
+
+int ip_masq_app_pkt_in(struct ip_masq *ms, struct sk_buff **skb_p, __u32 maddr)
+{
+ struct ip_masq_app * mapp;
+ struct iphdr *iph;
+ struct tcphdr *th;
+ int diff;
+ __u32 seq;
+
+ /*
+ * check if application masquerading is bound to
+ * this ip_masq.
+ * assumes that once an ip_masq is bound,
+ * it will not be unbound during its life.
+ */
+
+ if ( (mapp = ms->app) == NULL)
+ return 0;
+
+ iph = (*skb_p)->nh.iph;
+ th = (struct tcphdr *)&(((char *)iph)[iph->ihl*4]);
+
+ /*
+ * Remember seq number in case this pkt gets resized
+ */
+
+ seq = ntohl(th->seq);
+
+ /*
+ * Fix seq stuff if flagged as so.
+ */
+
+ if (ms->protocol == IPPROTO_TCP) {
+ if (ms->flags & IP_MASQ_F_IN_SEQ)
+ masq_fix_seq(&ms->in_seq, th);
+ if (ms->flags & IP_MASQ_F_OUT_SEQ)
+ masq_fix_ack_seq(&ms->out_seq, th);
+ }
+
+ /*
+ * Call private input hook function
+ */
+
+ if ( mapp->pkt_in == NULL )
+ return 0;
+
+ diff = mapp->pkt_in(mapp, ms, skb_p, maddr);
+
+ /*
+ * Update ip_masq seq stuff if len has changed.
+ */
+
+ if (diff != 0 && ms->protocol == IPPROTO_TCP)
+ masq_seq_update(ms, &ms->in_seq, IP_MASQ_F_IN_SEQ, seq, diff);
+
+ return diff;
+}
+
+/*
+ * /proc/ip_masq_app entry function
+ */
+
+int ip_masq_app_getinfo(char *buffer, char **start, off_t offset, int length, int dummy)
+{
+ off_t pos=0, begin=0;
+ int len=0;
+ struct ip_masq_app * mapp;
+ unsigned idx;
+
+ if (offset < 40)
+ len=sprintf(buffer,"%-39s\n", "prot port n_attach name");
+ pos = 40;
+
+ for (idx=0 ; idx < IP_MASQ_APP_TAB_SIZE; idx++)
+ for (mapp = ip_masq_app_base[idx]; mapp ; mapp = mapp->next) {
+ /*
+ * If you change the length of this sprintf, then all
+ * the length calculations need fixing too!
+ * Line length = 40 (3 + 2 + 7 + 1 + 7 + 1 + 2 + 17)
+ */
+ pos += 40;
+ if (pos < offset)
+ continue;
+
+ len += sprintf(buffer+len, "%-3s %-7u %-7d %-17s\n",
+ masq_proto_name(IP_MASQ_APP_PROTO(mapp->type)),
+ IP_MASQ_APP_PORT(mapp->type), mapp->n_attach,
+ mapp->name);
+
+ if(len >= length)
+ goto done;
+ }
+done:
+ begin = len - (pos - offset);
+ *start = buffer + begin;
+ len -= begin;
+ if (len > length)
+ len = length;
+ return len;
+}
+
+
+#ifdef CONFIG_PROC_FS
+static struct proc_dir_entry proc_net_ip_masq_app = {
+ PROC_NET_IP_MASQ_APP, 3, "app",
+ S_IFREG | S_IRUGO, 1, 0, 0,
+ 0, &proc_net_inode_operations,
+ ip_masq_app_getinfo
+};
+#endif
+
+/*
+ * Initialization routine
+ */
+
+__initfunc(int ip_masq_app_init(void))
+{
+#ifdef CONFIG_PROC_FS
+ ip_masq_proc_register(&proc_net_ip_masq_app);
+#endif
+ return 0;
+}
+
+/*
+ * Replace a segment (of skb->data) with a new one.
+ * FIXME: Should re-use same skb if space available, this could
+ * be done if n_len < o_len, unless some extra space
+ * were already allocated at driver level :P .
+ */
+
+static struct sk_buff * skb_replace(struct sk_buff *skb, int pri, char *o_buf, int o_len, char *n_buf, int n_len)
+{
+ int maxsize, diff, o_offset;
+ struct sk_buff *n_skb;
+ int offset;
+
+ maxsize = skb->truesize;
+
+ diff = n_len - o_len;
+ o_offset = o_buf - (char*) skb->data;
+
+ if (maxsize <= n_len) {
+ if (diff != 0) {
+ memcpy(skb->data + o_offset + n_len,o_buf + o_len,
+ skb->len - (o_offset + o_len));
+ }
+
+ memcpy(skb->data + o_offset, n_buf, n_len);
+
+ n_skb = skb;
+ skb->len = n_len;
+ skb->end = skb->head+n_len;
+ } else {
+ /*
+ * Sizes differ, make a copy.
+ *
+ * FIXME: move this to core/sbuff.c:skb_grow()
+ */
+
+ n_skb = alloc_skb(MAX_HEADER + skb->len + diff, pri);
+ if (n_skb == NULL) {
+ IP_MASQ_ERR("skb_replace(): no room left (from %p)\n",
+ __builtin_return_address(0));
+ return skb;
+
+ }
+ skb_reserve(n_skb, MAX_HEADER);
+ skb_put(n_skb, skb->len + diff);
+
+ /*
+ * Copy as much data from the old skb as possible. Even
+ * though we're only forwarding packets, we need stuff
+ * like skb->protocol (PPP driver wants it).
+ */
+ offset = n_skb->data - skb->data;
+ n_skb->nh.raw = skb->nh.raw + offset;
+ n_skb->h.raw = skb->h.raw + offset;
+ n_skb->dev = skb->dev;
+ n_skb->mac.raw = skb->mac.raw + offset;
+ n_skb->pkt_type = skb->pkt_type;
+ n_skb->protocol = skb->protocol;
+ n_skb->ip_summed = skb->ip_summed;
+ n_skb->dst = dst_clone(skb->dst);
+
+ /*
+ * Copy pkt in new buffer
+ */
+
+ memcpy(n_skb->data, skb->data, o_offset);
+ memcpy(n_skb->data + o_offset, n_buf, n_len);
+ memcpy(n_skb->data + o_offset + n_len, o_buf + o_len,
+ skb->len - (o_offset + o_len) );
+
+ /*
+ * Problem, how to replace the new skb with old one,
+ * preferably inplace
+ */
+
+ kfree_skb(skb);
+ }
+ return n_skb;
+}
+
+/*
+ * calls skb_replace() and update ip header if new skb was allocated
+ */
+
+struct sk_buff * ip_masq_skb_replace(struct sk_buff *skb, int pri, char *o_buf, int o_len, char *n_buf, int n_len)
+{
+ int diff;
+ struct sk_buff *n_skb;
+ unsigned skb_len;
+
+ diff = n_len - o_len;
+ n_skb = skb_replace(skb, pri, o_buf, o_len, n_buf, n_len);
+ skb_len = skb->len;
+
+ if (diff)
+ {
+ struct iphdr *iph;
+ IP_MASQ_DEBUG(1, "masq_skb_replace(): pkt resized for %d bytes (len=%d)\n", diff, skb->len);
+ /*
+ * update ip header
+ */
+ iph = n_skb->nh.iph;
+ iph->check = 0;
+ iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
+ iph->tot_len = htons(skb_len + diff);
+ }
+ return n_skb;
+}
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