1 /**
2  * @file
3  * SNMP RAW API frontend.
4  */
5 
6 /*
7  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without modification,
11  * are permitted provided that the following conditions are met:
12  *
13  * 1. Redistributions of source code must retain the above copyright notice,
14  *    this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright notice,
16  *    this list of conditions and the following disclaimer in the documentation
17  *    and/or other materials provided with the distribution.
18  * 3. The name of the author may not be used to endorse or promote products
19  *    derived from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
22  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
24  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
26  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
29  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
30  * OF SUCH DAMAGE.
31  *
32  * Author: Dirk Ziegelmeier <dziegel@gmx.de>
33  */
34 
35 #include "lwip/apps/snmp_opts.h"
36 #include "lwip/ip_addr.h"
37 
38 #if LWIP_SNMP && SNMP_USE_RAW
39 
40 #include "lwip/udp.h"
41 #include "lwip/ip.h"
42 #include "snmp_msg.h"
43 
44 /* lwIP UDP receive callback function */
45 static void
snmp_recv(void * arg,struct udp_pcb * pcb,struct pbuf * p,const ip_addr_t * addr,u16_t port)46 snmp_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
47 {
48   LWIP_UNUSED_ARG(arg);
49 
50   snmp_receive(pcb, p, addr, port);
51 
52   pbuf_free(p);
53 }
54 
55 err_t
snmp_sendto(void * handle,struct pbuf * p,const ip_addr_t * dst,u16_t port)56 snmp_sendto(void *handle, struct pbuf *p, const ip_addr_t *dst, u16_t port)
57 {
58   return udp_sendto((struct udp_pcb*)handle, p, dst, port);
59 }
60 
61 u8_t
snmp_get_local_ip_for_dst(void * handle,const ip_addr_t * dst,ip_addr_t * result)62 snmp_get_local_ip_for_dst(void* handle, const ip_addr_t *dst, ip_addr_t *result)
63 {
64   struct udp_pcb* udp_pcb = (struct udp_pcb*)handle;
65   struct netif *dst_if;
66   const ip_addr_t* dst_ip;
67 
68   LWIP_UNUSED_ARG(udp_pcb); /* unused in case of IPV4 only configuration */
69 
70   ip_route_get_local_ip(&udp_pcb->local_ip, dst, dst_if, dst_ip);
71 
72   if ((dst_if != NULL) && (dst_ip != NULL)) {
73     ip_addr_copy(*result, *dst_ip);
74     return 1;
75   } else {
76     return 0;
77   }
78 }
79 
80 /**
81  * @ingroup snmp_core
82  * Starts SNMP Agent.
83  * Allocates UDP pcb and binds it to IP_ANY_TYPE port 161.
84  */
85 void
snmp_init(void)86 snmp_init(void)
87 {
88   err_t err;
89 
90   struct udp_pcb *snmp_pcb = udp_new_ip_type(IPADDR_TYPE_ANY);
91   LWIP_ERROR("snmp_raw: no PCB", (snmp_pcb != NULL), return;);
92 
93   snmp_traps_handle = snmp_pcb;
94 
95   udp_recv(snmp_pcb, snmp_recv, (void *)SNMP_IN_PORT);
96   err = udp_bind(snmp_pcb, IP_ANY_TYPE, SNMP_IN_PORT);
97   LWIP_ERROR("snmp_raw: Unable to bind PCB", (err == ERR_OK), return;);
98 }
99 
100 #endif /* LWIP_SNMP && SNMP_USE_RAW */
101