Initial revision

1 files changed, 320 insertions, 0 deletions

diff --git a/gtp/pdp.c b/gtp/pdp.c
new file mode 100644
index 0000000..3e5951e
--- /dev/null
+++ b/gtp/pdp.c
@@ -0,0 +1,320 @@
+/* 
+ *  OpenGGSN - Gateway GPRS Support Node
+ *  Copyright (C) 2002 Mondru AB.
+ * 
+ *  The contents of this file may be used under the terms of the GNU
+ *  General Public License Version 2, provided that the above copyright
+ *  notice and this permission notice is included in all copies or
+ *  substantial portions of the software.
+ * 
+ *  The initial developer of the original code is
+ *  Jens Jakobsen <jj@openggsn.org>
+ * 
+ *  Contributor(s):
+ * 
+ */
+
+/*
+ * pdp.c: 
+ *
+ */
+
+#include <stdio.h>
+#include <sys/types.h>
+#include <netinet/in.h>
+#include <string.h>
+#include "pdp.h"
+#include "lookupa.h"
+
+/* ***********************************************************
+ * Global variables TODO: most should be moved to gsn_t
+ *************************************************************/
+
+struct pdp_t pdpa[PDP_MAX];    /* PDP storage */
+struct pdp_t* hashtid[PDP_MAX];/* Hash table for IMSI + NSAPI */
+struct pdp_t* haship[PDP_MAX]; /* Hash table for IP and network interface */
+
+/* ***********************************************************
+ * Functions related to PDP storage
+ *
+ * Lifecycle
+ * For a GGSN pdp context life begins with the reception of a 
+ * create pdp context request. It normally ends with the reception
+ * of a delete pdp context request, but will also end with the
+ * reception of an error indication message. 
+ * Provisions should probably be made for terminating pdp contexts
+ * based on either idle timeout, or by sending downlink probe 
+ * messages (ping?) to see if the MS is still responding.
+ * 
+ * For an SGSN pdp context life begins with the application just
+ * before sending off a create pdp context request. It normally
+ * ends when a delete pdp context response message is received 
+ * from the GGSN, but should also end when with the reception of
+ * an error indication message.
+ *
+ *
+ * HASH Tables
+ *
+ * Downlink packets received in the GGSN are identified only by their
+ * network interface together with their destination IP address (Two
+ * network interfaces can use the same private IP address). Each IMSI
+ * (mobile station) can have several PDP contexts using the same IP 
+ * address. In this case the traffic flow template (TFT) is used to
+ * determine the correct PDP context for a particular IMSI. Also it 
+ * should be possible for each PDP context to use several IP adresses
+ * For fixed wireless access a mobile station might need a full class
+ * C network. Even in the case of several IP adresses the PDP context
+ * should be determined on the basis of the network IP address.
+ * Thus we need a hash table based on network interface + IP address.
+ * 
+ * Uplink packets are for GTP0 identified by their IMSI and NSAPI, which
+ * is collectively called the tunnel identifier. There is also a 16 bit
+ * flow label that can be used for identification of uplink packets. This
+ * however is quite useless as it limits the number of contexts to 65536.
+ * For GTP1 uplink packets are identified by a Tunnel Endpoint Identifier
+ * (32 bit), or in some cases by the combination of IMSI and NSAPI.
+ * For GTP1 delete context requests there is a need to find the PDP
+ * contexts with the same IP address. This however can be done by using
+ * the IP hash table.
+ * Thus we need a hash table based on TID (IMSI and NSAPI). The TEID will
+ * be used for directly addressing the PDP context.
+
+ * pdp_newpdp 
+ * Gives you a pdp context with no hash references In some way
+ * this should have a limited lifetime.
+ *
+ * pdp_freepdp
+ * Frees a context that was previously allocated with
+ * pdp_newpdp
+ *
+ *
+ * pdp_getpdpIP
+ * An incoming IP packet is uniquely identified by a pointer
+ * to a network connection (void *) and an IP address
+ * (struct in_addr)
+ *
+ * pdp_getpdpGTP
+ * An incoming GTP packet is uniquely identified by a the
+ * TID (imsi + nsapi (8 octets)) in or by the Flow Label
+ * (2 octets) in gtp0 or by the Tunnel Endpoint Identifier
+ * (4 octets) in gtp1.
+ *
+ * This leads to an architecture where the receiving GSN
+ * chooses a Flow Label or a Tunnel Endpoint Identifier
+ * when the connection is setup.
+ * Thus no hash table is needed for GTP lookups.
+ *
+ *************************************************************/
+
+int pdp_init() {
+  memset(&pdpa, 0, sizeof(pdpa));
+  memset(&hashtid, 0, sizeof(hashtid));
+  memset(&haship, 0, sizeof(haship));
+
+  return 0;
+}
+
+int pdp_newpdp(struct pdp_t **pdp, uint64_t imsi, uint8_t nsapi, 
+	       struct pdp_t *pdp_old){
+  int n;
+  for (n=0; n<PDP_MAX; n++) { /* TODO: Need to do better than linear search */
+    if (pdpa[n].inuse == 0) {
+      *pdp = &pdpa[n];
+      if (NULL != pdp_old) memcpy(*pdp, pdp_old, sizeof(struct pdp_t));
+      else memset(*pdp, 0, sizeof(struct pdp_t));
+      (*pdp)->inuse    = 1;
+      (*pdp)->imsi     = imsi;
+      (*pdp)->nsapi    = nsapi;
+      (*pdp)->fllc     = (uint16_t) n;
+      (*pdp)->fllu     = (uint16_t) n;
+      (*pdp)->teic_own = (uint32_t) n;
+      (*pdp)->teic_own = (uint32_t) n;
+      pdp_tidset(*pdp, pdp_gettid(imsi, nsapi));
+      return 0;
+    }
+  }
+  return EOF; /* No more available */
+}
+
+int pdp_freepdp(struct pdp_t *pdp){
+  pdp_tiddel(pdp);
+  memset(pdp, 0, sizeof(struct pdp_t));
+  /* Also need to clean up IP hash tables */
+  return 0;
+}
+
+int pdp_getpdp(struct pdp_t **pdp){
+  *pdp = &pdpa[0];
+  return 0;
+}
+
+int pdp_getgtp0(struct pdp_t **pdp, uint16_t fl){
+  if (fl>=PDP_MAX) {
+    return EOF;  /* Not found */
+  }
+  else {
+    *pdp = &pdpa[fl];
+    if ((*pdp)->inuse) return 0;
+    else return EOF; 
+    /* Context exists. We do no further validity checking. */
+  }
+}
+
+int pdp_getgtp1(struct pdp_t **pdp, uint32_t teid){
+  if (teid>=PDP_MAX) {
+    return -1;  /* Not found */
+  }
+  else {
+    *pdp = &pdpa[teid];
+    return 0; /* We do no validity checking. */
+  }
+}
+
+
+int pdp_tidhash(uint64_t tid) {
+  return (lookup(&tid, sizeof(tid), 0) % PDP_MAX);
+}
+
+int pdp_tidset(struct pdp_t *pdp, uint64_t tid) {
+  int hash = pdp_tidhash(tid);
+  struct pdp_t *pdp2;
+  struct pdp_t *pdp_prev = NULL;
+  if (PDP_DEBUG) printf("Begin pdp_tidset tid = %llx\n", tid);
+  pdp->tid = tid;
+  for (pdp2 = hashtid[hash]; pdp2; pdp2 = pdp2->tidnext)
+    pdp_prev = pdp2;
+  if (!pdp_prev) 
+    hashtid[hash] = pdp;
+  else 
+    pdp_prev->tidnext = pdp;
+  if (PDP_DEBUG) printf("End pdp_tidset\n");
+  return 0;
+}
+
+int pdp_tiddel(struct pdp_t *pdp) {
+  int hash = pdp_tidhash(pdp->tid);
+  struct pdp_t *pdp2;
+  struct pdp_t *pdp_prev = NULL;
+  if (PDP_DEBUG) printf("Begin pdp_tiddel tid = %llx\n", pdp->tid);
+  for (pdp2 = hashtid[hash]; pdp2; pdp2 = pdp2->tidnext) {
+    if (pdp2 == pdp) {
+      if (!pdp_prev) 
+	hashtid[hash] = pdp2->tidnext;
+      else 
+	pdp_prev->tidnext = pdp2->tidnext;
+      if (PDP_DEBUG) printf("End pdp_tidset: PDP found\n");
+      return 0;
+    }
+    pdp_prev = pdp2;
+  }
+  if (PDP_DEBUG) printf("End pdp_tidset: PDP not found\n");
+  return EOF; /* End of linked list and not found */
+}
+
+int pdp_tidget(struct pdp_t **pdp, uint64_t tid) {
+  int hash = pdp_tidhash(tid);
+  struct pdp_t *pdp2;
+  if (PDP_DEBUG) printf("Begin pdp_tidget tid = %llx\n", tid);
+  for (pdp2 = hashtid[hash]; pdp2; pdp2 = pdp2->tidnext) {
+    if (pdp2->tid == tid) {
+      *pdp = pdp2;
+      if (PDP_DEBUG) printf("Begin pdp_tidget. Found\n");
+      return 0;
+    }
+  }
+  if (PDP_DEBUG) printf("Begin pdp_tidget. Not found\n");
+  return EOF; /* End of linked list and not found */
+}
+
+int pdp_iphash(void* ipif, struct ul66_t *eua) {
+  /*printf("IPhash %ld\n", lookup(eua->v, eua->l, ipif) % PDP_MAX);*/
+  return (lookup(eua->v, eua->l, ipif) % PDP_MAX);
+}
+    
+int pdp_ipset(struct pdp_t *pdp, void* ipif, struct ul66_t *eua) {
+  int hash;
+  struct pdp_t *pdp2;
+  struct pdp_t *pdp_prev = NULL;
+
+  if (PDP_DEBUG) printf("Begin pdp_ipset %d %d %2x%2x%2x%2x\n",
+			(unsigned) ipif, eua->l,
+			eua->v[2], eua->v[3], 
+			eua->v[4], eua->v[5]);
+
+  pdp->ipif = ipif;
+  pdp->eua.l = eua->l;
+  memcpy(pdp->eua.v, eua->v, eua->l);
+
+  hash = pdp_iphash(pdp->ipif, &pdp->eua);
+
+  for (pdp2 = haship[hash]; pdp2; pdp2 = pdp2->ipnext)
+    pdp_prev = pdp2;
+  if (!pdp_prev) 
+    haship[hash] = pdp;
+  else 
+    pdp_prev->ipnext = pdp;
+  if (PDP_DEBUG) printf("End pdp_ipset\n");
+  return 0;
+}
+
+int pdp_ipdel(struct pdp_t *pdp) {
+  int hash = pdp_iphash(pdp->ipif, &pdp->eua);
+  struct pdp_t *pdp2;
+  struct pdp_t *pdp_prev = NULL;
+  if (PDP_DEBUG) printf("Begin pdp_ipdel\n");
+  for (pdp2 = haship[hash]; pdp2; pdp2 = pdp2->ipnext) {
+    if (pdp2 == pdp) {
+      if (!pdp_prev) 
+	haship[hash] = pdp2->ipnext;
+      else 
+	pdp_prev->ipnext = pdp2->ipnext;
+      if (PDP_DEBUG) printf("End pdp_ipdel: PDP found\n");
+      return 0;
+    }
+    pdp_prev = pdp2;
+  }
+  if (PDP_DEBUG) printf("End pdp_ipdel: PDP not found\n");
+  return EOF; /* End of linked list and not found */
+}
+
+int pdp_ipget(struct pdp_t **pdp, void* ipif, struct ul66_t *eua) {
+  int hash = pdp_iphash(ipif, eua);
+  struct pdp_t *pdp2;
+  /*printf("Begin pdp_ipget %d %d %2x%2x%2x%2x\n", (unsigned)ipif, eua->l, 
+    eua->v[2],eua->v[3],eua->v[4],eua->v[5]);*/
+  for (pdp2 = haship[hash]; pdp2; pdp2 = pdp2->ipnext) {
+    if ((pdp2->ipif == ipif) && (pdp2->eua.l == eua->l) && 
+	(memcmp(&pdp2->eua.v, &eua->v, eua->l) == 0)) {
+      *pdp = pdp2;
+      /*printf("End pdp_ipget. Found\n");*/
+      return 0;
+    }
+  }
+  if (PDP_DEBUG) printf("End pdp_ipget Notfound %d %d %2x%2x%2x%2x\n", 
+	 (unsigned)ipif, eua->l, eua->v[2],eua->v[3],eua->v[4],eua->v[5]);
+  return EOF; /* End of linked list and not found */
+}
+
+/* Various conversion functions */
+
+int pdp_ntoeua(struct in_addr *src, struct ul66_t *eua) {
+  eua->l=6;
+  eua->v[0]=0xf1; /* IETF */
+  eua->v[1]=0x21; /* IPv4 */
+  memcpy(&eua->v[2], src, 4); /* Copy a 4 byte address */
+  return 0;
+}
+
+uint64_t pdp_gettid(uint64_t imsi, uint8_t nsapi) {
+  return (imsi & 0x0fffffffffffffff) + ((uint64_t)nsapi << 60);
+}
+
+int ulcpy(void* dst, void* src, size_t size) {
+  if (((struct ul255_t*)src)->l <= size) {
+    ((struct ul255_t*)dst)->l = ((struct ul255_t*)src)->l;
+    memcpy(((struct ul255_t*)dst)->v, ((struct ul255_t*)src)->v, 
+	   ((struct ul255_t*)dst)->l);
+    return 0;
+  }
+  else return EOF;
+}