Added minimalistic SNMP GET functionality.

CHANGELOG

@@ -25,6 +25,30 @@ HISTORY
 
   * [Enter new changes just after this line - do not remove this line]
 
+  ++ New features:
+  
+  2006-07-14 Christiaan Simons
+  * mib_structs.c: added
+  * include/lwip/snmp_structs.h: added
+  * netif.{c,h}, netif/ethernetif.c: added SNMP statistics to netif struct
+  * mib2.c: changed, inserted object tree
+  * msg_{in,out}.c: changed, added minimalistic GET functionality (needs work)
+
+  2006-07-06 Christiaan Simons
+  * snmp/asn1_{enc,dec}.c added
+  * snmp/mib2.c added
+  * snmp/msg_{in,out}.c added
+  * include/lwip/snmp_asn1.h added
+  * include/lwip/snmp_msg.h added
+  * doc/snmp_agent.txt added  
+
+  2006-03-29 Christiaan Simons
+  * inet.c, inet.h: Added platform byteswap support.
+    Added LWIP_PLATFORM_BYTESWAP define (defaults to 0) and
+    optional LWIP_PLATFORM_HTONS(), LWIP_PLATFORM_HTONL() macros.
+
+  ++ Bug fixes:
+    
   2006-06-27 Christiaan Simons
   * api_msg.c: Applied patch for cold case (bug #11135).
     In accept_function() ensure newconn->callback is always initialized.
@@ -41,11 +65,6 @@ HISTORY
   * api_lib.c: Removed conn->sem creation and destruction 
     from netconn_write() and added sys_sem_new to netconn_new_*.
 
-  2006-03-29 Christiaan Simons
-  * inet.c, inet.h: Added platform byteswap support.
-    Added LWIP_PLATFORM_BYTESWAP define (defaults to 0) and
-    optional LWIP_PLATFORM_HTONS(), LWIP_PLATFORM_HTONL() macros.
-
 (STABLE-1_1_1)
 
   2006-03-03  Christiaan Simons

src/core/snmp/mib_structs.c

@@ -0,0 +1,224 @@
+/**
+ * @file
+ * [EXPERIMENTAL] Generic MIB tree access/construction functions.
+ */
+
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ */
+
+#include "lwip/opt.h"
+#include "lwip/snmp_structs.h"
+
+#if LWIP_SNMP
+
+/**
+ * Searches tree for the supplied (scalar?) object identifier.
+ *
+ * @param node points to the root of the tree ('.internet')
+ * @param ident_len the length of the supplied object identifier
+ * @param ident points to the array of sub identifiers
+ * @param object_def points to the object definition to return
+ * @return pointer to the requested parent (!) node if success, NULL otherwise
+ */
+struct mib_node *
+snmp_search_tree(struct mib_node *node, u8_t ident_len, s32_t *ident, struct obj_def *object_def)
+{
+  u8_t node_type;
+
+  LWIP_DEBUGF(SNMP_MIB_DEBUG,("node==%p *ident==%"S32_F,(void*)node,*ident));
+  while (node != NULL)
+  {
+    node_type = node->node_type;
+    if ((node_type == MIB_NODE_AR) || (node_type == MIB_NODE_RA))
+    {
+      struct mib_array_node *an;
+      u16_t i;
+
+      /* array node (internal ROM or RAM, fixed length) */
+      an = (struct mib_array_node *)node;
+      i = 0;
+      while ((i < an->maxlength) && (an->objid[i] != *ident))
+      {
+        i++;
+      }
+      if (i < an->maxlength)
+      {
+        if (ident_len > 0)
+        { 
+          /* found it, if available proceed to child, otherwise inspect leaf */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("an->objid[%"U16_F"]==%"S32_F" *ident==%"S32_F,i,an->objid[i],*ident));
+          if (an->nptr[i] == NULL)
+          {
+            /* a scalar leaf OR table,
+               inspect remaining instance number / table index */
+            /* retrieve object definition with get_object_def() 
+               is it scalar, or a valid table item, or non-existent? */
+            an->get_object_def(ident_len, ident, object_def);
+            if (object_def->instance != MIB_OBJECT_NONE)
+            {
+              /** @todo return something more usefull ?? */
+              return (struct mib_node*)an;
+            }
+            else
+            {
+              /* search failed, object id points to unknown object (nosuchname) */
+              LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed, object not in this MIB"));
+              return NULL;
+            }
+          }
+          else
+          {
+            /* follow next child pointer */
+            ident++;
+            ident_len--;
+            node = an->nptr[i];
+          }
+        }
+        else
+        {
+          /* search failed, short object identifier (nosuchname) */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed, short object identifier"));
+          return NULL;
+        }
+      }
+      else
+      {
+        /* search failed, identifier mismatch (nosuchname) */
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed *ident==%"S32_F,*ident));
+        return NULL;
+      }
+    }
+    else if(node_type == MIB_NODE_LR)
+    {
+      struct mib_list_rootnode *lrn;
+      struct mib_list_node *ln;
+
+      /* list root node (internal 'RAM', variable length) */
+      lrn = (struct mib_list_rootnode *)node;
+      ln = lrn->head;
+      /* iterate over list, head to tail */
+      while ((ln != NULL) && (ln->objid != *ident))
+      {
+        ln = ln->next;
+      }
+      if (ln != NULL)
+      {
+        if (ident_len > 0)
+        { 
+          /* found it, proceed to child */;
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("ln->objid==%"S32_F" *ident==%"S32_F,ln->objid,*ident));
+          if (ln->nptr == NULL)
+          {
+            lrn->get_object_def(ident_len, ident, object_def);
+            if (object_def->instance != MIB_OBJECT_NONE)
+            {
+              /** @todo return something more usefull ?? */
+              return (struct mib_node*)lrn;
+            }
+            else
+            {
+              /* search failed, object id points to unknown object (nosuchname) */
+              LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed, object not in this MIB"));
+              return NULL;
+            }
+          }
+          else
+          {
+            /* follow next child pointer */
+            ident_len--;
+            ident++;
+            node = ln->nptr;
+          }
+        }
+        else
+        {
+          /* search failed, short object identifier (nosuchname) */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed, short object identifier"));
+          return NULL;
+        }
+      }
+      else
+      {
+        /* search failed */
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed *ident==%"S32_F,*ident));
+        return NULL;
+      }
+    }
+    else if(node_type == MIB_NODE_EX)
+    {
+      struct mib_external_node *en;
+      u16_t i;
+
+      /* external node (addressing and access via functions) */
+      en = (struct mib_external_node *)node;
+      i = 0;
+      while ((i < en->count) && en->ident_cmp(i,*ident))
+      {
+        i++;
+      }
+      if (i < en->count)
+      {
+        if (ident_len > 0)
+        { 
+          if (en->get_nptr(i) == NULL)
+          {
+/** @todo, this object is elsewhere, we can only start the request,
+     but can't return something usefull yet.*/
+            en->req_object_def(ident_len, ident);
+            return (struct mib_node*)en;
+          }
+          else
+          {
+            /* found it, proceed to child */
+            ident_len--;
+            ident++;
+            node = (struct mib_node*)en->get_nptr(i);
+          }
+        }
+        else
+        {
+          /* search failed, short object identifier (nosuchname) */
+          LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed, short object identifier"));
+          return NULL;
+        }
+      }
+      else
+      {
+        /* search failed */
+        LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed *ident==%"S32_F,*ident));
+        return NULL;
+      }
+    }
+  }
+  /* done, found nothing */
+  LWIP_DEBUGF(SNMP_MIB_DEBUG,("search failed node==%p",(void*)node));
+  return NULL;
+}
+
+#endif /* LWIP_SNMP */

src/core/snmp/msg_in.c

@@ -47,9 +47,11 @@
 #include "lwip/snmp_asn1.h"
 #include "lwip/snmp_msg.h"
 
+#include "lwip/snmp_structs.h"
 
 #if LWIP_SNMP
 
+#define LWIP_SNMP_DBG_LOOPBACK_TST 0
 #define SNMP_CONCURRENT_REQUESTS 2
 
 /* public (non-static) constants */
@@ -72,8 +74,16 @@ static void snmp_varbind_list_free(struct snmp_varbind_root *root);
 static void snmp_varbind_tail_add(struct snmp_varbind_root *root, struct snmp_varbind *vb);
 static struct snmp_varbind* snmp_varbind_tail_remove(struct snmp_varbind_root *root);
 
+/** @todo: move this to  header */
+extern const struct mib_array_node internet;
+extern const struct mib_array_node sys_tem; /* test only */
 
-void snmp_init(void)
+/**
+ * Starts SNMP Agent.
+ * Allocates UDP pcb and binds it to IP_ADDR_ANY port 161.
+ */
+void
+snmp_init(void)
 {
   struct snmp_msg_pstat *msg_ps;
   u8_t i;
@@ -95,6 +105,14 @@ void snmp_init(void)
   trap_msg.pcb = snmp1_pcb;
 }
 
+/**
+ *
+ */
+void
+snmp_msg_event(void)
+{
+}
+
 /* lwIP UDP receive callback function */
 static void
 snmp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr, u16_t port)
@@ -155,14 +173,65 @@ snmp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *addr,
         err_ret = snmp_pdu_dec_varbindlist(p, varbind_ofs, &varbind_ofs, msg_ps);
         if (err_ret == ERR_OK)
         {          
+          struct mib_node *mn;
+          struct obj_def object_def;
+
           /* we've decoded the incoming message, release input msg now */
           pbuf_free(p);
 
           LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv varbind cnt=%"U16_F"\n",(u16_t)msg_ps->invb.count));
 
+          if (msg_ps->rt == SNMP_ASN1_PDU_GET_REQ)
+          { 
+            /** @todo check if count > 0 and if we got .iso.dod.internet  and iterate from vb 0 .. count-1 */
+            mn = snmp_search_tree((struct mib_node*)&internet, msg_ps->invb.head->ident_len - 2 /* trim iso.dod.internet */,
+                                   msg_ps->invb.head->ident + 2, &object_def);
+            if (mn != NULL)
+            {
+              LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv mn=%p sys_tem=%p node_typ=%"U16_F,
+                                            (void*)mn,(void*)&sys_tem,(u16_t)mn->node_type));
+          
+              if (msg_ps->invb.head->value != NULL)
+              {
+                LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv free value before vb recycle"));
+                mem_free(msg_ps->invb.head->value);
+              }            
+              msg_ps->invb.head->value_type = object_def.asn_type;
+              msg_ps->invb.head->value_len = object_def.v_len;
+              msg_ps->invb.head->value = mem_malloc(object_def.v_len);
+              if (msg_ps->invb.head->value != NULL)
+              {
+                mn->get_value(object_def.id_inst_len, object_def.id_inst_ptr, object_def.v_len, msg_ps->invb.head->value);
+              }
+              else
+              {
+                LWIP_DEBUGF(SNMP_MSG_DEBUG, ("snmp_recv couldn't allocate variable space"));
+              }
+              msg_ps->outvb = msg_ps->invb;
+            }
+            else
+            {
+              /* mn == NULL, noSuchName */
+              msg_ps->error_status = SNMP_ES_NOSUCHNAME;
+              /** @todo current varbind index */
+              msg_ps->error_index = 1;
+              msg_ps->outvb.head = NULL;
+              msg_ps->outvb.tail = NULL;
+              msg_ps->outvb.count = 0;
+              msg_ps->outvb.seqlen = 0;
+              msg_ps->outvb.seqlenlen = 1;
+            }
+          }
+          else
+          {
+            /* request != GET */
             /** @todo EXPERIMENTAL dumb echo, this is not how the agent should respond.
                 This is for test purposes only, do not use this in real world!! */
             msg_ps->outvb = msg_ps->invb;
+            msg_ps->error_status = SNMP_ES_NOERROR;
+            msg_ps->error_index = 0;
+          }
+
           err_ret = snmp_send_response(msg_ps);
           if (err_ret == ERR_MEM)
           {

src/core/snmp/msg_out.c

@@ -76,7 +76,7 @@ static u16_t snmp_varbind_list_enc(struct snmp_varbind_root *root, struct pbuf *
  * @return ERR_OK when success, ERR_MEM if we're out of memory
  *
  * @note the caller is responsible for filling in outvb in the m_stat
- * @todo caller must provide error-status and index ...
+ * and provide error-status and index (except for tooBig errors) ...
  */
 err_t
 snmp_send_response(struct snmp_msg_pstat *m_stat)
@@ -86,9 +86,6 @@ snmp_send_response(struct snmp_msg_pstat *m_stat)
   u16_t tot_len;
   err_t err;
 
-  m_stat->error_status = SNMP_ES_NOERROR;
-  m_stat->error_index = 0;
-
   /* pass 0, calculate length fields */
   tot_len = snmp_varbind_list_sum(&m_stat->outvb);
   tot_len = snmp_resp_header_sum(m_stat, tot_len);
@@ -207,12 +204,12 @@ snmp_send_trap(struct ip_addr *dst, s8_t generic_trap, s32_t specific_trap)
   if (generic_trap == 6)
   {
     /* enterprise-Specific trap */
-    snmp_get_sysobjid(&trap_msg.enterprise);
+    snmp_get_sysobjid_ptr(&trap_msg.enterprise);
   }
   else
   {
     /* generic (MIB-II) trap */    
-    snmp_get_snmpgrpid(&trap_msg.enterprise);
+    snmp_get_snmpgrpid_ptr(&trap_msg.enterprise);
   }
   snmp_get_sysuptime(&trap_msg.ts);
 

src/include/lwip/snmp.h

@@ -49,7 +49,7 @@ struct snmp_obj_id
 };
 
 /* system */
-void snmp_set_sysdesr(char* str, u8_t strlen);
+void snmp_set_sysdesr(u8_t* str, u8_t strlen);
 void snmp_set_sysobjid(struct snmp_obj_id *oid);
 void snmp_get_sysobjid_ptr(struct snmp_obj_id **oid);
 void snmp_inc_sysuptime(void);

src/include/lwip/snmp_structs.h

@@ -0,0 +1,179 @@
+/**
+ * @file
+ * [EXPERIMENTAL] Generic MIB tree structures.
+ *
+ * @todo namespace prefixes
+ */
+
+/*
+ * Copyright (c) 2006 Axon Digital Design B.V., The Netherlands.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * Author: Christiaan Simons <christiaan.simons@axon.tv>
+ */
+
+#ifndef __LWIP_SNMP_STRUCTS_H__
+#define __LWIP_SNMP_STRUCTS_H__
+
+#include "lwip/opt.h"
+#include "arch/cc.h"
+
+#if SNMP_PRIVATE_MIB
+#include "private_mib.h"
+#endif
+
+/* MIB object instance */
+#define MIB_OBJECT_NONE 0 
+#define MIB_OBJECT_SCALAR 1
+#define MIB_OBJECT_TAB 2
+
+/* MIB object access */
+#define MIB_OBJECT_READ_ONLY 0
+#define MIB_OBJECT_READ_WRITE 1
+#define MIB_OBJECT_WRITE_ONLY 2
+#define MIB_OBJECT_NOT_ACCESSIBLE 3
+
+/** object definition returned by (get_object_def)() */
+struct obj_def
+{
+  /* MIB_OBJECT_NONE (0), MIB_OBJECT_SCALAR (1), MIB_OBJECT_TAB (2) */
+  u8_t instance;
+  /* 0 read-only, 1 read-write, 2 write-only, 3 not-accessible */
+  u8_t access;
+  /* ASN type for this object */
+  u8_t asn_type;
+  /* value length (host length) */
+  u16_t v_len;
+  /* length of instance part of supplied object identifier */
+  u8_t  id_inst_len;
+  /* instance part of supplied object identifier */
+  s32_t *id_inst_ptr; 
+};
+
+/** MIB const array node */
+#define MIB_NODE_AR 0x01
+/** MIB array node (mem_malloced from RAM) */
+#define MIB_NODE_RA 0x02
+/** MIB list root node (mem_malloced from RAM) */
+#define MIB_NODE_LR 0x03
+/** MIB node for external objects */
+#define MIB_NODE_EX 0x04
+
+/** node "base class" layout, the mandatory fields for a node  */
+struct mib_node
+{
+  /** returns struct obj_def for the given object identifier */
+  void (*get_object_def)(u8_t ident_len, s32_t *ident, struct obj_def *od);
+  /** returns object value for the given object identifier,
+     @note the caller must allocate at least len bytes for the value */
+  void (*get_value)(u8_t ident_len, s32_t *ident, u16_t len, void *value);
+  /** @todo set_value() */
+  /** One out of MIB_NODE_AR, MIB_NODE_LR or MIB_NODE_EX */
+  const u8_t node_type;
+  /* array or max list length */
+  const u16_t maxlength;
+};
+
+/** derived node, points to a fixed size const array
+    of sub-identifiers plus a 'child' pointer */
+struct mib_array_node
+{
+  /* inherited "base class" */
+  const void (*get_object_def)(u8_t ident_len, s32_t *ident, struct obj_def *od);
+  const void (*get_value)(u8_t ident_len, s32_t *ident, u16_t len, void *value);
+  const u8_t node_type;
+  const u16_t maxlength;
+
+  /* aditional struct members */
+  const s32_t *objid;
+  struct mib_node* const *nptr;
+};
+
+/** derived node, points to a fixed size mem_malloced array
+    of sub-identifiers plus a 'child' pointer */
+struct mib_ram_array_node
+{
+  /* inherited "base class" */
+  void (*get_object_def)(u8_t ident_len, s32_t *ident, struct obj_def *od);
+  void (*get_value)(u8_t ident_len, s32_t *ident, u16_t len, void *value);
+  u8_t node_type;
+  u16_t maxlength;
+
+  /* aditional struct members */
+  s32_t *objid;
+  struct mib_node **nptr;
+};
+
+struct mib_list_node
+{
+  struct mib_list_node *prev;  
+  struct mib_list_node *next;
+  s32_t objid;
+  struct mib_node *nptr;
+};
+
+/** derived node, points to a doubly linked list
+    of sub-identifiers plus a 'child' pointer */
+struct mib_list_rootnode
+{
+  /* inherited "base class" */
+  void (*get_object_def)(u8_t ident_len, s32_t *ident, struct obj_def *od);
+  void (*get_value)(u8_t ident_len, s32_t *ident, u16_t len, void *value);
+  u8_t node_type;
+  u16_t maxlength;
+
+  /* aditional struct members */
+  struct mib_list_node *head;
+  struct mib_list_node *tail;
+  /* counts list nodes in list  */
+  u16_t count;
+};
+
+/** derived node, has access functions for mib object in external memory or device
+    using index ('idx'), with a range 0 .. (count - 1) to address these objects */
+struct mib_external_node
+{
+  /* inherited "base class" */
+  void (*get_object_def)(u8_t ident_len, s32_t *ident, struct obj_def *od);
+  void (*get_value)(u8_t ident_len, s32_t *ident, u16_t len, void *value);
+  u8_t node_type;
+  u16_t maxlength;
+
+  /* aditional struct members */
+  void (*req_object_def)(u8_t ident_len, s32_t *ident);
+  void (*getreq_value)(u8_t ident_len, s32_t *ident);
+
+  /** compares object sub identifier with externally available id
+      return zero when equal, nonzero when unequal */
+  u16_t (*ident_cmp)(u16_t idx, s32_t sub_id);
+  /** returns next pointer for given index (NULL for scalar 'leaf') */
+  struct mib_extern_node* (*get_nptr)(u16_t idx);
+  /* counts actual number of external objects  */
+  u16_t count;
+};
+
+struct mib_node* snmp_search_tree(struct mib_node *node, u8_t ident_len, s32_t *ident, struct obj_def *object_def);
+
+#endif