From dc3fad8c60650e2bd67d95edb01ca0eb3bb23b3d Mon Sep 17 00:00:00 2001
From: John Crispin <blogic@openwrt.org>
Date: Thu, 29 Sep 2011 20:29:54 +0200
Subject: [PATCH 17/25] udp in-kernel redirect

---
 include/linux/udp_redirect.h |   57 +++++++++++++
 net/Kconfig                  |    6 ++
 net/ipv4/Makefile            |    3 +
 net/ipv4/udp.c               |   28 ++++++-
 net/ipv4/udp_redirect_symb.c |  186 ++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 276 insertions(+), 4 deletions(-)
 create mode 100644 include/linux/udp_redirect.h
 create mode 100644 net/ipv4/udp_redirect_symb.c

diff --git a/include/linux/udp_redirect.h b/include/linux/udp_redirect.h
new file mode 100644
index 0000000..de1e64f
--- /dev/null
+++ b/include/linux/udp_redirect.h
@@ -0,0 +1,57 @@
+#ifndef _UDP_REDIRECT_H
+#define _UDP_REDIRECT_H
+
+/******************************************************************************
+
+                               Copyright (c) 2006
+                            Infineon Technologies AG
+                     Am Campeon 1-12; 81726 Munich, Germany
+
+  THE DELIVERY OF THIS SOFTWARE AS WELL AS THE HEREBY GRANTED NON-EXCLUSIVE,
+  WORLDWIDE LICENSE TO USE, COPY, MODIFY, DISTRIBUTE AND SUBLICENSE THIS
+  SOFTWARE IS FREE OF CHARGE.
+
+  THE LICENSED SOFTWARE IS PROVIDED "AS IS" AND INFINEON EXPRESSLY DISCLAIMS
+  ALL REPRESENTATIONS AND WARRANTIES, WHETHER EXPRESS OR IMPLIED, INCLUDING
+  WITHOUT LIMITATION, WARRANTIES OR REPRESENTATIONS OF WORKMANSHIP,
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, DURABILITY, THAT THE
+  OPERATING OF THE LICENSED SOFTWARE WILL BE ERROR FREE OR FREE OF ANY THIRD
+  PARTY CLAIMS, INCLUDING WITHOUT LIMITATION CLAIMS OF THIRD PARTY INTELLECTUAL
+  PROPERTY INFRINGEMENT.
+
+  EXCEPT FOR ANY LIABILITY DUE TO WILFUL ACTS OR GROSS NEGLIGENCE AND EXCEPT
+  FOR ANY PERSONAL INJURY INFINEON SHALL IN NO EVENT BE LIABLE FOR ANY CLAIM
+  OR DAMAGES OF ANY KIND, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+  ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+  DEALINGS IN THE SOFTWARE.
+
+******************************************************************************/
+
+/* ============================= */
+/* Includes                      */
+/* ============================= */
+#ifndef _LINUX_TYPES_H
+#include <linux/types.h>
+#endif
+
+
+/* ============================= */
+/* Definitions                   */
+/* ============================= */
+#define UDP_REDIRECT_MAGIC (void*)0x55445052L
+
+
+/* ============================= */
+/* Global variable declaration   */
+/* ============================= */
+extern int (*udp_do_redirect_fn)(struct sock *sk, struct sk_buff *skb);
+extern int (*udpredirect_getfrag_fn)(void *p, char * to,
+                                     int offset, int fraglen, int odd,
+                                     struct sk_buff *skb);
+/* ============================= */
+/* Global function declaration   */
+/* ============================= */
+
+extern int udpredirect_getfrag(void *p, char * to, int offset,
+                               int fraglen, int odd, struct sk_buff *skb);
+#endif
diff --git a/net/Kconfig b/net/Kconfig
index b3904e8..be5e417 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -78,6 +78,12 @@ config INET
 
 	  Short answer: say Y.
 
+config IFX_UDP_REDIRECT
+	bool "IFX Kernel Packet Interface for UDP redirection"
+	help
+	  You can say Y here if you want to use hooks from kernel for
+	  UDP redirection.
+
 if INET
 source "net/ipv4/Kconfig"
 source "net/ipv6/Kconfig"
diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile
index 1d57fe0..9974d6e 100644
--- a/net/ipv4/Makefile
+++ b/net/ipv4/Makefile
@@ -14,6 +14,9 @@ obj-y     := route.o inetpeer.o protocol.o \
 	     inet_fragment.o ping.o
 
 obj-$(CONFIG_SYSCTL) += sysctl_net_ipv4.o
+ifneq ($(CONFIG_IFX_UDP_REDIRECT),)
+obj-$(CONFIG_IFX_UDP_REDIRECT) += udp_redirect_symb.o
+endif
 obj-$(CONFIG_PROC_FS) += proc.o
 obj-$(CONFIG_IP_MULTIPLE_TABLES) += fib_rules.o
 obj-$(CONFIG_IP_MROUTE) += ipmr.o
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 5d075b5..a2ee1bf 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -108,6 +108,10 @@
 #include <trace/events/udp.h>
 #include "udp_impl.h"
 
+#if defined(CONFIG_IFX_UDP_REDIRECT) || defined(CONFIG_IFX_UDP_REDIRECT_MODULE)
+#include <linux/udp_redirect.h>
+#endif
+
 struct udp_table udp_table __read_mostly;
 EXPORT_SYMBOL(udp_table);
 
@@ -804,7 +808,7 @@ int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 	u8  tos;
 	int err, is_udplite = IS_UDPLITE(sk);
 	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
-	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
+	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *) = NULL;
 	struct sk_buff *skb;
 	struct ip_options_data opt_copy;
 
@@ -821,7 +825,13 @@ int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 	ipc.opt = NULL;
 	ipc.tx_flags = 0;
 
-	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
+/* UDPREDIRECT */
+#if defined(CONFIG_IFX_UDP_REDIRECT) || defined(CONFIG_IFX_UDP_REDIRECT_MODULE)
+	if(udpredirect_getfrag_fn && sk->sk_user_data == UDP_REDIRECT_MAGIC)
+		getfrag = udpredirect_getfrag_fn;
+	else
+#endif /* IFX_UDP_REDIRECT */
+		getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
 
 	fl4 = &inet->cork.fl.u.ip4;
 	if (up->pending) {
@@ -1625,6 +1635,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	struct rtable *rt = skb_rtable(skb);
 	__be32 saddr, daddr;
 	struct net *net = dev_net(skb->dev);
+	int ret = 0;
 
 	/*
 	 *  Validate the packet.
@@ -1657,7 +1668,16 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
 
 	if (sk != NULL) {
-		int ret = udp_queue_rcv_skb(sk, skb);
+	/* UDPREDIRECT */
+#if defined(CONFIG_IFX_UDP_REDIRECT) || defined(CONFIG_IFX_UDP_REDIRECT_MODULE)
+      if(udp_do_redirect_fn && sk->sk_user_data == UDP_REDIRECT_MAGIC)
+      {
+         udp_do_redirect_fn(sk,skb);
+         kfree_skb(skb);
+         return(0);
+      }
+#endif
+		ret = udp_queue_rcv_skb(sk, skb);
 		sock_put(sk);
 
 		/* a return value > 0 means to resubmit the input, but
@@ -1954,7 +1974,7 @@ struct proto udp_prot = {
 	.clear_sk	   = sk_prot_clear_portaddr_nulls,
 };
 EXPORT_SYMBOL(udp_prot);
-
+EXPORT_SYMBOL(udp_rcv);
 /* ------------------------------------------------------------------------ */
 #ifdef CONFIG_PROC_FS
 
diff --git a/net/ipv4/udp_redirect_symb.c b/net/ipv4/udp_redirect_symb.c
new file mode 100644
index 0000000..5617e86
--- /dev/null
+++ b/net/ipv4/udp_redirect_symb.c
@@ -0,0 +1,186 @@
+/******************************************************************************
+
+                               Copyright (c) 2006
+                            Infineon Technologies AG
+                     Am Campeon 1-12; 81726 Munich, Germany
+
+  THE DELIVERY OF THIS SOFTWARE AS WELL AS THE HEREBY GRANTED NON-EXCLUSIVE,
+  WORLDWIDE LICENSE TO USE, COPY, MODIFY, DISTRIBUTE AND SUBLICENSE THIS
+  SOFTWARE IS FREE OF CHARGE.
+
+  THE LICENSED SOFTWARE IS PROVIDED "AS IS" AND INFINEON EXPRESSLY DISCLAIMS
+  ALL REPRESENTATIONS AND WARRANTIES, WHETHER EXPRESS OR IMPLIED, INCLUDING
+  WITHOUT LIMITATION, WARRANTIES OR REPRESENTATIONS OF WORKMANSHIP,
+  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, DURABILITY, THAT THE
+  OPERATING OF THE LICENSED SOFTWARE WILL BE ERROR FREE OR FREE OF ANY THIRD
+  PARTY CLAIMS, INCLUDING WITHOUT LIMITATION CLAIMS OF THIRD PARTY INTELLECTUAL
+  PROPERTY INFRINGEMENT.
+
+  EXCEPT FOR ANY LIABILITY DUE TO WILFUL ACTS OR GROSS NEGLIGENCE AND EXCEPT
+  FOR ANY PERSONAL INJURY INFINEON SHALL IN NO EVENT BE LIABLE FOR ANY CLAIM
+  OR DAMAGES OF ANY KIND, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+  ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+  DEALINGS IN THE SOFTWARE.
+
+******************************************************************************/
+#if defined(CONFIG_IFX_UDP_REDIRECT) || defined(CONFIG_IFX_UDP_REDIRECT_MODULE)
+/* ============================= */
+/* Includes                      */
+/* ============================= */
+#include <net/checksum.h>
+#include <net/udp.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/udp_redirect.h>
+
+/* ============================= */
+/* Global variable definition    */
+/* ============================= */
+int (*udpredirect_getfrag_fn) (void *p, char * to, int offset,
+                               int fraglen, int odd, struct sk_buff *skb) = NULL;
+int (*udp_do_redirect_fn)(struct sock *sk, struct sk_buff *skb) = NULL;
+
+/* ============================= */
+/* Local type definitions        */
+/* ============================= */
+struct udpfakehdr
+{
+  struct udphdr uh;
+  u32 saddr;
+  u32 daddr;
+  struct iovec *iov;
+  u32 wcheck;
+};
+
+/* ============================= */
+/* Local function declaration    */
+/* ============================= */
+static int udpredirect_csum_partial_copy_fromiovecend(unsigned char *kdata,
+              struct iovec *iov, int offset, unsigned int len, __wsum *csump);
+
+static int udpredirect_memcpy_fromiovecend(unsigned char *kdata, struct iovec *iov, int offset,
+                        int len);
+
+/* ============================= */
+/* Global function definition    */
+/* ============================= */
+
+/*
+   Copy of udp_getfrag() from udp.c
+   This function exists because no copy_from_user() is needed for udpredirect.
+*/
+
+int
+udpredirect_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
+{
+   struct iovec *iov = from;
+
+        if (skb->ip_summed == CHECKSUM_PARTIAL) {
+                if (udpredirect_memcpy_fromiovecend(to, iov, offset, len) < 0)
+                        return -EFAULT;
+        } else {
+                __wsum csum = 0;
+                if (udpredirect_csum_partial_copy_fromiovecend(to, iov, offset, len, &csum) < 0)
+                        return -EFAULT;
+                skb->csum = csum_block_add(skb->csum, csum, odd);
+        }
+        return 0;
+}
+
+static int udpredirect_memcpy_fromiovecend(unsigned char *kdata, struct iovec *iov, int offset,
+                        int len)
+{
+        /* Skip over the finished iovecs */
+        while (offset >= iov->iov_len) {
+                offset -= iov->iov_len;
+                iov++;
+        }
+
+        while (len > 0) {
+                u8 __user *base = iov->iov_base + offset;
+                int copy = min_t(unsigned int, len, iov->iov_len - offset);
+
+                offset = 0;
+                memcpy(kdata, base, copy);
+                len -= copy;
+                kdata += copy;
+                iov++;
+        }
+
+        return 0;
+}
+
+/*
+   Copy of csum_partial_copy_fromiovecend() from iovec.c
+   This function exists because no copy_from_user() is needed for udpredirect.
+*/
+
+int udpredirect_csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov,
+				 int offset, unsigned int len, __wsum *csump)
+{
+	__wsum csum = *csump;
+	int partial_cnt = 0, err = 0;
+
+	/* Skip over the finished iovecs */
+	while (offset >= iov->iov_len) {
+		offset -= iov->iov_len;
+		iov++;
+	}
+
+	while (len > 0) {
+		u8 __user *base = iov->iov_base + offset;
+		int copy = min_t(unsigned int, len, iov->iov_len - offset);
+
+		offset = 0;
+
+		/* There is a remnant from previous iov. */
+		if (partial_cnt) {
+			int par_len = 4 - partial_cnt;
+
+			/* iov component is too short ... */
+			if (par_len > copy) {
+				memcpy(kdata, base, copy);
+				kdata += copy;
+				base  += copy;
+				partial_cnt += copy;
+				len   -= copy;
+				iov++;
+				if (len)
+					continue;
+				*csump = csum_partial(kdata - partial_cnt,
+							 partial_cnt, csum);
+				goto out;
+			}
+			memcpy(kdata, base, par_len);
+			csum = csum_partial(kdata - partial_cnt, 4, csum);
+			kdata += par_len;
+			base  += par_len;
+			copy  -= par_len;
+			len   -= par_len;
+			partial_cnt = 0;
+		}
+
+		if (len > copy) {
+			partial_cnt = copy % 4;
+			if (partial_cnt) {
+				copy -= partial_cnt;
+				memcpy(kdata + copy, base + copy, partial_cnt);
+			}
+		}
+
+		if (copy) {
+			csum = csum_partial_copy_nocheck(base, kdata, copy, csum);
+		}
+		len   -= copy + partial_cnt;
+		kdata += copy + partial_cnt;
+		iov++;
+	}
+        *csump = csum;
+out:
+	return err;
+}
+
+EXPORT_SYMBOL(udpredirect_getfrag);
+EXPORT_SYMBOL(udp_do_redirect_fn);
+EXPORT_SYMBOL(udpredirect_getfrag_fn);
+#endif /* CONFIG_IFX_UDP_REDIRECT* */
-- 
1.7.9.1

