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9f4eb5cc RG |
1 | #include "snmp-agent.hh" |
2 | #include "misc.hh" | |
519f5484 | 3 | #include "threadname.hh" |
77c9bc9a | 4 | #ifdef RECURSOR |
c390b2da | 5 | #include "logger.hh" |
77c9bc9a PL |
6 | #else |
7 | #include "dolog.hh" | |
8 | #endif | |
9f4eb5cc RG |
9 | |
10 | #ifdef HAVE_NET_SNMP | |
11 | ||
0e663c3b RG |
12 | #ifndef HAVE_SNMP_SELECT_INFO2 |
13 | /* that's terrible, because it means we are going to have trouble with large | |
14 | FD numbers at some point.. */ | |
15 | # define netsnmp_large_fd_set fd_set | |
16 | # define snmp_read2 snmp_read | |
17 | # define snmp_select_info2 snmp_select_info | |
18 | # define netsnmp_large_fd_set_init(...) | |
19 | # define netsnmp_large_fd_set_cleanup(...) | |
20 | # define NETSNMP_LARGE_FD_SET FD_SET | |
21 | # define NETSNMP_LARGE_FD_CLR FD_CLR | |
22 | # define NETSNMP_LARGE_FD_ZERO FD_ZERO | |
23 | # define NETSNMP_LARGE_FD_ISSET FD_ISSET | |
24 | #else | |
25 | # include <net-snmp/library/large_fd_set.h> | |
26 | #endif | |
27 | ||
9f4eb5cc RG |
28 | const oid SNMPAgent::snmpTrapOID[] = { 1, 3, 6, 1, 6, 3, 1, 1, 4, 1, 0 }; |
29 | const size_t SNMPAgent::snmpTrapOIDLen = OID_LENGTH(SNMPAgent::snmpTrapOID); | |
30 | ||
31 | int SNMPAgent::setCounter64Value(netsnmp_request_info* request, | |
32 | uint64_t value) | |
33 | { | |
34 | struct counter64 val64; | |
35 | val64.high = value >> 32; | |
36 | val64.low = value & 0xffffffff; | |
37 | snmp_set_var_typed_value(request->requestvb, | |
38 | ASN_COUNTER64, | |
39 | &val64, | |
40 | sizeof(val64)); | |
41 | return SNMP_ERR_NOERROR; | |
42 | } | |
43 | ||
44 | bool SNMPAgent::sendTrap(int fd, | |
45 | netsnmp_variable_list* varList) | |
46 | { | |
47 | ssize_t written = write(fd, &varList, sizeof(varList)); | |
48 | ||
49 | if (written != sizeof(varList)) { | |
50 | snmp_free_varbind(varList); | |
51 | return false; | |
52 | } | |
53 | return true; | |
54 | } | |
55 | ||
0e663c3b | 56 | void SNMPAgent::handleTrapsEvent() |
9f4eb5cc RG |
57 | { |
58 | netsnmp_variable_list* varList = nullptr; | |
59 | ssize_t got = 0; | |
60 | ||
61 | do { | |
62 | got = read(d_trapPipe[0], &varList, sizeof(varList)); | |
63 | ||
64 | if (got == sizeof(varList)) { | |
65 | send_v2trap(varList); | |
66 | snmp_free_varbind(varList); | |
67 | } | |
68 | } | |
69 | while (got > 0); | |
70 | } | |
0e663c3b RG |
71 | |
72 | void SNMPAgent::handleSNMPQueryEvent(int fd) | |
73 | { | |
74 | netsnmp_large_fd_set fdset; | |
75 | netsnmp_large_fd_set_init(&fdset, FD_SETSIZE); | |
76 | NETSNMP_LARGE_FD_ZERO(&fdset); | |
77 | NETSNMP_LARGE_FD_SET(fd, &fdset); | |
78 | snmp_read2(&fdset); | |
79 | } | |
80 | ||
81 | void SNMPAgent::handleTrapsCB(int fd, FDMultiplexer::funcparam_t& var) | |
82 | { | |
83 | SNMPAgent** agent = boost::any_cast<SNMPAgent*>(&var); | |
84 | if (!agent || !*agent) | |
85 | throw std::runtime_error("Invalid value received in SNMP trap callback"); | |
86 | ||
87 | (*agent)->handleTrapsEvent(); | |
88 | } | |
89 | ||
90 | void SNMPAgent::handleSNMPQueryCB(int fd, FDMultiplexer::funcparam_t& var) | |
91 | { | |
92 | SNMPAgent** agent = boost::any_cast<SNMPAgent*>(&var); | |
93 | if (!agent || !*agent) | |
94 | throw std::runtime_error("Invalid value received in SNMP trap callback"); | |
95 | ||
96 | (*agent)->handleSNMPQueryEvent(fd); | |
97 | } | |
98 | ||
9f4eb5cc RG |
99 | #endif /* HAVE_NET_SNMP */ |
100 | ||
101 | void SNMPAgent::worker() | |
102 | { | |
103 | #ifdef HAVE_NET_SNMP | |
4226cfd0 | 104 | FDMultiplexer* mplexer = FDMultiplexer::getMultiplexerSilent(); |
0e663c3b RG |
105 | if (mplexer == nullptr) { |
106 | throw std::runtime_error("No FD multiplexer found for the SNMP agent!"); | |
107 | } | |
108 | ||
77c9bc9a | 109 | #ifdef RECURSOR |
c390b2da | 110 | string threadName = "pdns-r/SNMP"; |
77c9bc9a PL |
111 | #else |
112 | string threadName = "dnsdist/SNMP"; | |
113 | #endif | |
519f5484 | 114 | setThreadName(threadName); |
c390b2da | 115 | |
0e663c3b | 116 | int maxfd = 0; |
9f4eb5cc | 117 | int block = 1; |
0e663c3b | 118 | netsnmp_large_fd_set fdset; |
9f4eb5cc | 119 | struct timeval timeout = { 0, 0 }; |
0e663c3b RG |
120 | struct timeval now; |
121 | ||
122 | /* we want to be notified if a trap is waiting | |
123 | to be sent */ | |
124 | mplexer->addReadFD(d_trapPipe[0], &handleTrapsCB, this); | |
9f4eb5cc RG |
125 | |
126 | while(true) { | |
0e663c3b RG |
127 | netsnmp_large_fd_set_init(&fdset, FD_SETSIZE); |
128 | NETSNMP_LARGE_FD_ZERO(&fdset); | |
9f4eb5cc | 129 | |
0576fe19 RG |
130 | block = 1; |
131 | timeout = { 0, 0 }; | |
0e663c3b | 132 | snmp_select_info2(&maxfd, &fdset, &timeout, &block); |
9f4eb5cc | 133 | |
0e663c3b RG |
134 | for (int fd = 0; fd < maxfd; fd++) { |
135 | if (NETSNMP_LARGE_FD_ISSET(fd, &fdset)) { | |
136 | mplexer->addReadFD(fd, &handleSNMPQueryCB, this); | |
9f4eb5cc RG |
137 | } |
138 | } | |
0e663c3b RG |
139 | |
140 | /* run updates now */ | |
141 | int res = mplexer->run(&now, (timeout.tv_sec * 1000) + (timeout.tv_usec / 1000)); | |
142 | ||
143 | /* we handle timeouts here, the rest has already been handled by callbacks */ | |
144 | if (res == 0) { | |
9f4eb5cc | 145 | snmp_timeout(); |
0576fe19 | 146 | run_alarms(); |
9f4eb5cc | 147 | } |
0e663c3b RG |
148 | |
149 | for (int fd = 0; fd < maxfd; fd++) { | |
150 | if (NETSNMP_LARGE_FD_ISSET(fd, &fdset)) { | |
151 | try { | |
152 | mplexer->removeReadFD(fd); | |
153 | } | |
154 | catch(const FDMultiplexerException& e) { | |
155 | /* we might get an exception when removing a closed file descriptor, | |
156 | just ignore it */ | |
157 | } | |
158 | } | |
159 | } | |
9f4eb5cc RG |
160 | } |
161 | #endif /* HAVE_NET_SNMP */ | |
162 | } | |
163 | ||
164 | SNMPAgent::SNMPAgent(const std::string& name, const std::string& masterSocket) | |
165 | { | |
166 | #ifdef HAVE_NET_SNMP | |
167 | netsnmp_enable_subagent(); | |
168 | snmp_disable_log(); | |
169 | if (!masterSocket.empty()) { | |
170 | netsnmp_ds_set_string(NETSNMP_DS_APPLICATION_ID, | |
171 | NETSNMP_DS_AGENT_X_SOCKET, | |
172 | masterSocket.c_str()); | |
173 | } | |
174 | /* no need to load any MIBS, | |
175 | and it causes import errors if some modules are not present */ | |
176 | setenv("MIBS", "", 1); | |
177 | ||
178 | init_agent(name.c_str()); | |
0576fe19 RG |
179 | |
180 | /* we use select() so don't use SIGALARM to handle alarms. | |
181 | Note that we need to handle alarms for automatic reconnection | |
182 | to the master to work. | |
183 | */ | |
184 | netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID, | |
185 | NETSNMP_DS_LIB_ALARM_DONT_USE_SIG, | |
186 | 1); | |
187 | ||
9f4eb5cc RG |
188 | init_snmp(name.c_str()); |
189 | ||
190 | if (pipe(d_trapPipe) < 0) | |
191 | unixDie("Creating pipe"); | |
192 | ||
193 | if (!setNonBlocking(d_trapPipe[0])) { | |
194 | close(d_trapPipe[0]); | |
195 | close(d_trapPipe[1]); | |
196 | unixDie("Setting pipe non-blocking"); | |
197 | } | |
198 | ||
199 | if (!setNonBlocking(d_trapPipe[1])) { | |
200 | close(d_trapPipe[0]); | |
201 | close(d_trapPipe[1]); | |
202 | unixDie("Setting pipe non-blocking"); | |
203 | } | |
204 | ||
205 | #endif /* HAVE_NET_SNMP */ | |
206 | } |