PF_RING patch for Linux 2.4.26 (tested with 2.4.26 and .25, but should work
with earlier versions too) made by Georg Lukas <g.lukas@intergenia.de>

This patch is based on work by Luca Deri (see http://luca.ntop.org/Ring.pdf
for more details).

--- linux-2.4.26/net/core/dev.c	2004-02-18 14:36:32.000000000 +0100
+++ linux-2.4.26-pfring/net/core/dev.c	2004-02-06 12:40:47.000000000 +0100
@@ -108,6 +108,16 @@
 extern int plip_init(void);
 #endif
 
+#define RING
+/* #define RING_DEBUG */
+
+#ifdef RING
+#include <linux/ring.h>
+
+handle_ring_skb ring_handler = NULL;
+EXPORT_SYMBOL(ring_handler);
+
+#endif
 
 /* This define, if set, will randomly drop a packet when congestion
  * is more than moderate.  It helps fairness in the multi-interface
@@ -1278,6 +1288,13 @@
 	struct softnet_data *queue;
 	unsigned long flags;
 
+#ifdef RING
+	if(ring_handler && ring_handler(skb)) {
+	  /* The packet has been copied into a ring */
+	  return(NET_RX_SUCCESS);
+	}
+#endif /* RING */
+
 	if (skb->stamp.tv_sec == 0)
 		do_gettimeofday(&skb->stamp);
 
@@ -1464,6 +1481,13 @@
 	int ret = NET_RX_DROP;
 	unsigned short type = skb->protocol;
 
+#ifdef RING
+	if(ring_handler && ring_handler(skb)) {
+	  /* The packet has been copied into a ring */
+	  return(NET_RX_SUCCESS);
+	}
+#endif /* RING */
+
 	if (skb->stamp.tv_sec == 0)
 		do_gettimeofday(&skb->stamp);
 
--- linux-2.4.26/include/net/sock.h	2004-03-04 12:14:43.000000000 +0100
+++ linux-2.4.26-pfring/include/net/sock.h	2004-02-06 12:37:24.000000000 +0100
@@ -645,6 +645,9 @@
 #if defined (CONFIG_PACKET) || defined(CONFIG_PACKET_MODULE)
 		struct packet_opt	*af_packet;
 #endif
+	  /* L. Deri */
+	  struct ring_opt *pf_ring;
+
 #if defined(CONFIG_X25) || defined(CONFIG_X25_MODULE)
 		x25_cb			*x25;
 #endif
--- linux-2.4.26/include/linux/ring.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-2.4.26-pfring/include/linux/ring.h	2004-02-06 12:37:24.000000000 +0100
@@ -0,0 +1,65 @@
+/*
+ * Definitions for packet ring
+ *
+ * 2004 - Luca Deri <deri@ntop.org>
+ */
+#ifndef __RING_H
+#define __RING_H
+
+
+#define INCLUDE_MAC_INFO
+
+#ifdef INCLUDE_MAC_INFO
+#define SKB_DISPLACEMENT    14 /* Include MAC address information */
+#else
+#define SKB_DISPLACEMENT    0  /* Do NOT include MAC address information */
+#endif
+
+typedef struct flowSlotInfo {
+  u_int tot_slots, slot_len, sample_rate, tot_num_pages, pkts_per_page;
+  u_int32_t tot_pkts, tot_lost;
+  u_short insert_idx;
+  u_short remove_idx;
+} FlowSlotInfo;
+
+typedef struct flowSlot {
+  u_char     slot_state; /* 0=empty, 1=full */
+  u_short    slot_len;
+  u_char     bucket;    /* bucket[bucketLen] */
+} FlowSlot;
+
+/* *********************************** */
+
+#ifndef HAVE_PCAP
+struct pcap_pkthdr {
+  struct timeval ts;    /* time stamp */
+  u_int32_t caplen;     /* length of portion present */
+  u_int32_t len;        /* length this packet (off wire) */
+};
+#endif
+
+/* *********************************** */
+
+#ifdef __KERNEL__ 
+FlowSlotInfo* getRingPtr(void);
+int allocateRing(char *deviceName, u_int numSlots, u_int bucketLen, u_int sampleRate);
+unsigned int pollRing(struct file *fp, struct poll_table_struct * wait);
+void deallocateRing(void);
+
+/* ************************* */
+
+typedef int (*handle_ring_skb)(struct sk_buff *skb);
+
+#endif /* __KERNEL__  */
+
+/* *********************************** */
+
+#define PF_RING          27      /* Packet Ring */
+#define SOCK_RING        PF_RING
+
+/* ioctl() */
+#define SIORINGPOLL      0x8888
+
+/* *********************************** */
+
+#endif /* __RING_H */
--- linux-2.4.26/net/core/Makefile	2003-11-28 19:26:21.000000000 +0100
+++ linux-2.4.26-pfring/net/core/Makefile	2004-04-23 01:01:59.000000000 +0200
@@ -9,7 +9,7 @@
 
 O_TARGET := core.o
 
-export-objs := netfilter.o profile.o
+export-objs := dev.o netfilter.o profile.o
 
 obj-y := sock.o skbuff.o iovec.o datagram.o scm.o