1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 #include <stdlib.h>
17 #include <string.h>
18
19 #define LOG_TAG "NetlinkEvent"
20 #include <cutils/log.h>
21
22 #include <sysutils/NetlinkEvent.h>
23
24 #include <sys/types.h>
25 #include <sys/socket.h>
26 #include <netinet/in.h>
27 #include <netinet/icmp6.h>
28 #include <arpa/inet.h>
29 #include <net/if.h>
30
31 #include <linux/if.h>
32 #include <linux/if_addr.h>
33 #include <linux/if_link.h>
34 #include <linux/netfilter/nfnetlink.h>
35 #include <linux/netfilter_ipv4/ipt_ULOG.h>
36 /* From kernel's net/netfilter/xt_quota2.c */
37 const int QLOG_NL_EVENT = 112;
38
39 #include <linux/netlink.h>
40 #include <linux/rtnetlink.h>
41
42 const int NetlinkEvent::NlActionUnknown = 0;
43 const int NetlinkEvent::NlActionAdd = 1;
44 const int NetlinkEvent::NlActionRemove = 2;
45 const int NetlinkEvent::NlActionChange = 3;
46 const int NetlinkEvent::NlActionLinkUp = 4;
47 const int NetlinkEvent::NlActionLinkDown = 5;
48 const int NetlinkEvent::NlActionAddressUpdated = 6;
49 const int NetlinkEvent::NlActionAddressRemoved = 7;
50 const int NetlinkEvent::NlActionRdnss = 8;
51 const int NetlinkEvent::NlActionRouteUpdated = 9;
52 const int NetlinkEvent::NlActionRouteRemoved = 10;
53
NetlinkEvent()54 NetlinkEvent::NetlinkEvent() {
55 mAction = NlActionUnknown;
56 memset(mParams, 0, sizeof(mParams));
57 mPath = NULL;
58 mSubsystem = NULL;
59 }
60
~NetlinkEvent()61 NetlinkEvent::~NetlinkEvent() {
62 int i;
63 if (mPath)
64 free(mPath);
65 if (mSubsystem)
66 free(mSubsystem);
67 for (i = 0; i < NL_PARAMS_MAX; i++) {
68 if (!mParams[i])
69 break;
70 free(mParams[i]);
71 }
72 }
73
dump()74 void NetlinkEvent::dump() {
75 int i;
76
77 for (i = 0; i < NL_PARAMS_MAX; i++) {
78 if (!mParams[i])
79 break;
80 SLOGD("NL param '%s'\n", mParams[i]);
81 }
82 }
83
84 /*
85 * Returns the message name for a message in the NETLINK_ROUTE family, or NULL
86 * if parsing that message is not supported.
87 */
rtMessageName(int type)88 static const char *rtMessageName(int type) {
89 #define NL_EVENT_RTM_NAME(rtm) case rtm: return #rtm;
90 switch (type) {
91 NL_EVENT_RTM_NAME(RTM_NEWLINK);
92 NL_EVENT_RTM_NAME(RTM_DELLINK);
93 NL_EVENT_RTM_NAME(RTM_NEWADDR);
94 NL_EVENT_RTM_NAME(RTM_DELADDR);
95 NL_EVENT_RTM_NAME(RTM_NEWROUTE);
96 NL_EVENT_RTM_NAME(RTM_DELROUTE);
97 NL_EVENT_RTM_NAME(RTM_NEWNDUSEROPT);
98 NL_EVENT_RTM_NAME(QLOG_NL_EVENT);
99 default:
100 return NULL;
101 }
102 #undef NL_EVENT_RTM_NAME
103 }
104
105 /*
106 * Checks that a binary NETLINK_ROUTE message is long enough for a payload of
107 * size bytes.
108 */
checkRtNetlinkLength(const struct nlmsghdr * nh,size_t size)109 static bool checkRtNetlinkLength(const struct nlmsghdr *nh, size_t size) {
110 if (nh->nlmsg_len < NLMSG_LENGTH(size)) {
111 SLOGE("Got a short %s message\n", rtMessageName(nh->nlmsg_type));
112 return false;
113 }
114 return true;
115 }
116
117 /*
118 * Utility function to log errors.
119 */
maybeLogDuplicateAttribute(bool isDup,const char * attributeName,const char * messageName)120 static bool maybeLogDuplicateAttribute(bool isDup,
121 const char *attributeName,
122 const char *messageName) {
123 if (isDup) {
124 SLOGE("Multiple %s attributes in %s, ignoring\n", attributeName, messageName);
125 return true;
126 }
127 return false;
128 }
129
130 /*
131 * Parse a RTM_NEWLINK message.
132 */
parseIfInfoMessage(const struct nlmsghdr * nh)133 bool NetlinkEvent::parseIfInfoMessage(const struct nlmsghdr *nh) {
134 struct ifinfomsg *ifi = (struct ifinfomsg *) NLMSG_DATA(nh);
135 if (!checkRtNetlinkLength(nh, sizeof(*ifi)))
136 return false;
137
138 if ((ifi->ifi_flags & IFF_LOOPBACK) != 0) {
139 return false;
140 }
141
142 int len = IFLA_PAYLOAD(nh);
143 struct rtattr *rta;
144 for (rta = IFLA_RTA(ifi); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
145 switch(rta->rta_type) {
146 case IFLA_IFNAME:
147 asprintf(&mParams[0], "INTERFACE=%s", (char *) RTA_DATA(rta));
148 mAction = (ifi->ifi_flags & IFF_LOWER_UP) ? NlActionLinkUp :
149 NlActionLinkDown;
150 mSubsystem = strdup("net");
151 return true;
152 }
153 }
154
155 return false;
156 }
157
158 /*
159 * Parse a RTM_NEWADDR or RTM_DELADDR message.
160 */
parseIfAddrMessage(const struct nlmsghdr * nh)161 bool NetlinkEvent::parseIfAddrMessage(const struct nlmsghdr *nh) {
162 struct ifaddrmsg *ifaddr = (struct ifaddrmsg *) NLMSG_DATA(nh);
163 struct ifa_cacheinfo *cacheinfo = NULL;
164 char addrstr[INET6_ADDRSTRLEN] = "";
165 char ifname[IFNAMSIZ];
166
167 if (!checkRtNetlinkLength(nh, sizeof(*ifaddr)))
168 return false;
169
170 // Sanity check.
171 int type = nh->nlmsg_type;
172 if (type != RTM_NEWADDR && type != RTM_DELADDR) {
173 SLOGE("parseIfAddrMessage on incorrect message type 0x%x\n", type);
174 return false;
175 }
176
177 // For log messages.
178 const char *msgtype = rtMessageName(type);
179
180 struct rtattr *rta;
181 int len = IFA_PAYLOAD(nh);
182 for (rta = IFA_RTA(ifaddr); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
183 if (rta->rta_type == IFA_ADDRESS) {
184 // Only look at the first address, because we only support notifying
185 // one change at a time.
186 if (maybeLogDuplicateAttribute(*addrstr != '\0', "IFA_ADDRESS", msgtype))
187 continue;
188
189 // Convert the IP address to a string.
190 if (ifaddr->ifa_family == AF_INET) {
191 struct in_addr *addr4 = (struct in_addr *) RTA_DATA(rta);
192 if (RTA_PAYLOAD(rta) < sizeof(*addr4)) {
193 SLOGE("Short IPv4 address (%zu bytes) in %s",
194 RTA_PAYLOAD(rta), msgtype);
195 continue;
196 }
197 inet_ntop(AF_INET, addr4, addrstr, sizeof(addrstr));
198 } else if (ifaddr->ifa_family == AF_INET6) {
199 struct in6_addr *addr6 = (struct in6_addr *) RTA_DATA(rta);
200 if (RTA_PAYLOAD(rta) < sizeof(*addr6)) {
201 SLOGE("Short IPv6 address (%zu bytes) in %s",
202 RTA_PAYLOAD(rta), msgtype);
203 continue;
204 }
205 inet_ntop(AF_INET6, addr6, addrstr, sizeof(addrstr));
206 } else {
207 SLOGE("Unknown address family %d\n", ifaddr->ifa_family);
208 continue;
209 }
210
211 // Find the interface name.
212 if (!if_indextoname(ifaddr->ifa_index, ifname)) {
213 SLOGE("Unknown ifindex %d in %s", ifaddr->ifa_index, msgtype);
214 return false;
215 }
216
217 } else if (rta->rta_type == IFA_CACHEINFO) {
218 // Address lifetime information.
219 if (maybeLogDuplicateAttribute(cacheinfo, "IFA_CACHEINFO", msgtype))
220 continue;
221
222 if (RTA_PAYLOAD(rta) < sizeof(*cacheinfo)) {
223 SLOGE("Short IFA_CACHEINFO (%zu vs. %zu bytes) in %s",
224 RTA_PAYLOAD(rta), sizeof(cacheinfo), msgtype);
225 continue;
226 }
227
228 cacheinfo = (struct ifa_cacheinfo *) RTA_DATA(rta);
229 }
230 }
231
232 if (addrstr[0] == '\0') {
233 SLOGE("No IFA_ADDRESS in %s\n", msgtype);
234 return false;
235 }
236
237 // Fill in netlink event information.
238 mAction = (type == RTM_NEWADDR) ? NlActionAddressUpdated :
239 NlActionAddressRemoved;
240 mSubsystem = strdup("net");
241 asprintf(&mParams[0], "ADDRESS=%s/%d", addrstr,
242 ifaddr->ifa_prefixlen);
243 asprintf(&mParams[1], "INTERFACE=%s", ifname);
244 asprintf(&mParams[2], "FLAGS=%u", ifaddr->ifa_flags);
245 asprintf(&mParams[3], "SCOPE=%u", ifaddr->ifa_scope);
246
247 if (cacheinfo) {
248 asprintf(&mParams[4], "PREFERRED=%u", cacheinfo->ifa_prefered);
249 asprintf(&mParams[5], "VALID=%u", cacheinfo->ifa_valid);
250 asprintf(&mParams[6], "CSTAMP=%u", cacheinfo->cstamp);
251 asprintf(&mParams[7], "TSTAMP=%u", cacheinfo->tstamp);
252 }
253
254 return true;
255 }
256
257 /*
258 * Parse a QLOG_NL_EVENT message.
259 */
parseUlogPacketMessage(const struct nlmsghdr * nh)260 bool NetlinkEvent::parseUlogPacketMessage(const struct nlmsghdr *nh) {
261 const char *devname;
262 ulog_packet_msg_t *pm = (ulog_packet_msg_t *) NLMSG_DATA(nh);
263 if (!checkRtNetlinkLength(nh, sizeof(*pm)))
264 return false;
265
266 devname = pm->indev_name[0] ? pm->indev_name : pm->outdev_name;
267 asprintf(&mParams[0], "ALERT_NAME=%s", pm->prefix);
268 asprintf(&mParams[1], "INTERFACE=%s", devname);
269 mSubsystem = strdup("qlog");
270 mAction = NlActionChange;
271 return true;
272 }
273
274 /*
275 * Parse a RTM_NEWROUTE or RTM_DELROUTE message.
276 */
parseRtMessage(const struct nlmsghdr * nh)277 bool NetlinkEvent::parseRtMessage(const struct nlmsghdr *nh) {
278 uint8_t type = nh->nlmsg_type;
279 const char *msgname = rtMessageName(type);
280
281 // Sanity check.
282 if (type != RTM_NEWROUTE && type != RTM_DELROUTE) {
283 SLOGE("%s: incorrect message type %d (%s)\n", __func__, type, msgname);
284 return false;
285 }
286
287 struct rtmsg *rtm = (struct rtmsg *) NLMSG_DATA(nh);
288 if (!checkRtNetlinkLength(nh, sizeof(*rtm)))
289 return false;
290
291 if (// Ignore static routes we've set up ourselves.
292 (rtm->rtm_protocol != RTPROT_KERNEL &&
293 rtm->rtm_protocol != RTPROT_RA) ||
294 // We're only interested in global unicast routes.
295 (rtm->rtm_scope != RT_SCOPE_UNIVERSE) ||
296 (rtm->rtm_type != RTN_UNICAST) ||
297 // We don't support source routing.
298 (rtm->rtm_src_len != 0) ||
299 // Cloned routes aren't real routes.
300 (rtm->rtm_flags & RTM_F_CLONED)) {
301 return false;
302 }
303
304 int family = rtm->rtm_family;
305 int prefixLength = rtm->rtm_dst_len;
306
307 // Currently we only support: destination, (one) next hop, ifindex.
308 char dst[INET6_ADDRSTRLEN] = "";
309 char gw[INET6_ADDRSTRLEN] = "";
310 char dev[IFNAMSIZ] = "";
311
312 size_t len = RTM_PAYLOAD(nh);
313 struct rtattr *rta;
314 for (rta = RTM_RTA(rtm); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
315 switch (rta->rta_type) {
316 case RTA_DST:
317 if (maybeLogDuplicateAttribute(*dst, "RTA_DST", msgname))
318 continue;
319 if (!inet_ntop(family, RTA_DATA(rta), dst, sizeof(dst)))
320 return false;
321 continue;
322 case RTA_GATEWAY:
323 if (maybeLogDuplicateAttribute(*gw, "RTA_GATEWAY", msgname))
324 continue;
325 if (!inet_ntop(family, RTA_DATA(rta), gw, sizeof(gw)))
326 return false;
327 continue;
328 case RTA_OIF:
329 if (maybeLogDuplicateAttribute(*dev, "RTA_OIF", msgname))
330 continue;
331 if (!if_indextoname(* (int *) RTA_DATA(rta), dev))
332 return false;
333 default:
334 continue;
335 }
336 }
337
338 // If there's no RTA_DST attribute, then:
339 // - If the prefix length is zero, it's the default route.
340 // - If the prefix length is nonzero, there's something we don't understand.
341 // Ignore the event.
342 if (!*dst && !prefixLength) {
343 if (family == AF_INET) {
344 strncpy(dst, "0.0.0.0", sizeof(dst));
345 } else if (family == AF_INET6) {
346 strncpy(dst, "::", sizeof(dst));
347 }
348 }
349
350 // A useful route must have a destination and at least either a gateway or
351 // an interface.
352 if (!*dst || (!*gw && !*dev))
353 return false;
354
355 // Fill in netlink event information.
356 mAction = (type == RTM_NEWROUTE) ? NlActionRouteUpdated :
357 NlActionRouteRemoved;
358 mSubsystem = strdup("net");
359 asprintf(&mParams[0], "ROUTE=%s/%d", dst, prefixLength);
360 asprintf(&mParams[1], "GATEWAY=%s", (*gw) ? gw : "");
361 asprintf(&mParams[2], "INTERFACE=%s", (*dev) ? dev : "");
362
363 return true;
364 }
365
366 /*
367 * Parse a RTM_NEWNDUSEROPT message.
368 */
parseNdUserOptMessage(const struct nlmsghdr * nh)369 bool NetlinkEvent::parseNdUserOptMessage(const struct nlmsghdr *nh) {
370 struct nduseroptmsg *msg = (struct nduseroptmsg *) NLMSG_DATA(nh);
371 if (!checkRtNetlinkLength(nh, sizeof(*msg)))
372 return false;
373
374 // Check the length is valid.
375 int len = NLMSG_PAYLOAD(nh, sizeof(*msg));
376 if (msg->nduseropt_opts_len > len) {
377 SLOGE("RTM_NEWNDUSEROPT invalid length %d > %d\n",
378 msg->nduseropt_opts_len, len);
379 return false;
380 }
381 len = msg->nduseropt_opts_len;
382
383 // Check address family and packet type.
384 if (msg->nduseropt_family != AF_INET6) {
385 SLOGE("RTM_NEWNDUSEROPT message for unknown family %d\n",
386 msg->nduseropt_family);
387 return false;
388 }
389
390 if (msg->nduseropt_icmp_type != ND_ROUTER_ADVERT ||
391 msg->nduseropt_icmp_code != 0) {
392 SLOGE("RTM_NEWNDUSEROPT message for unknown ICMPv6 type/code %d/%d\n",
393 msg->nduseropt_icmp_type, msg->nduseropt_icmp_code);
394 return false;
395 }
396
397 // Find the interface name.
398 char ifname[IFNAMSIZ];
399 if (!if_indextoname(msg->nduseropt_ifindex, ifname)) {
400 SLOGE("RTM_NEWNDUSEROPT on unknown ifindex %d\n",
401 msg->nduseropt_ifindex);
402 return false;
403 }
404
405 // The kernel sends a separate netlink message for each ND option in the RA.
406 // So only parse the first ND option in the message.
407 struct nd_opt_hdr *opthdr = (struct nd_opt_hdr *) (msg + 1);
408
409 // The length is in multiples of 8 octets.
410 uint16_t optlen = opthdr->nd_opt_len;
411 if (optlen * 8 > len) {
412 SLOGE("Invalid option length %d > %d for ND option %d\n",
413 optlen * 8, len, opthdr->nd_opt_type);
414 return false;
415 }
416
417 if (opthdr->nd_opt_type == ND_OPT_RDNSS) {
418 // DNS Servers (RFC 6106).
419 // Each address takes up 2*8 octets, and the header takes up 8 octets.
420 // So for a valid option with one or more addresses, optlen must be
421 // odd and greater than 1.
422 if ((optlen < 3) || !(optlen & 0x1)) {
423 SLOGE("Invalid optlen %d for RDNSS option\n", optlen);
424 return false;
425 }
426 int numaddrs = (optlen - 1) / 2;
427
428 // Find the lifetime.
429 struct nd_opt_rdnss *rndss_opt = (struct nd_opt_rdnss *) opthdr;
430 uint32_t lifetime = ntohl(rndss_opt->nd_opt_rdnss_lifetime);
431
432 // Construct "SERVERS=<comma-separated string of DNS addresses>".
433 // Reserve (INET6_ADDRSTRLEN + 1) chars for each address: all but the
434 // the last address are followed by ','; the last is followed by '\0'.
435 static const char kServerTag[] = "SERVERS=";
436 static const int kTagLength = sizeof(kServerTag) - 1;
437 int bufsize = kTagLength + numaddrs * (INET6_ADDRSTRLEN + 1);
438 char *buf = (char *) malloc(bufsize);
439 if (!buf) {
440 SLOGE("RDNSS option: out of memory\n");
441 return false;
442 }
443 strcpy(buf, kServerTag);
444 int pos = kTagLength;
445
446 struct in6_addr *addrs = (struct in6_addr *) (rndss_opt + 1);
447 for (int i = 0; i < numaddrs; i++) {
448 if (i > 0) {
449 buf[pos++] = ',';
450 }
451 inet_ntop(AF_INET6, addrs + i, buf + pos, bufsize - pos);
452 pos += strlen(buf + pos);
453 }
454 buf[pos] = '\0';
455
456 mAction = NlActionRdnss;
457 mSubsystem = strdup("net");
458 asprintf(&mParams[0], "INTERFACE=%s", ifname);
459 asprintf(&mParams[1], "LIFETIME=%u", lifetime);
460 mParams[2] = buf;
461 } else {
462 SLOGD("Unknown ND option type %d\n", opthdr->nd_opt_type);
463 return false;
464 }
465
466 return true;
467 }
468
469 /*
470 * Parse a binary message from a NETLINK_ROUTE netlink socket.
471 *
472 * Note that this function can only parse one message, because the message's
473 * content has to be stored in the class's member variables (mAction,
474 * mSubsystem, etc.). Invalid or unrecognized messages are skipped, but if
475 * there are multiple valid messages in the buffer, only the first one will be
476 * returned.
477 *
478 * TODO: consider only ever looking at the first message.
479 */
parseBinaryNetlinkMessage(char * buffer,int size)480 bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) {
481 const struct nlmsghdr *nh;
482
483 for (nh = (struct nlmsghdr *) buffer;
484 NLMSG_OK(nh, (unsigned) size) && (nh->nlmsg_type != NLMSG_DONE);
485 nh = NLMSG_NEXT(nh, size)) {
486
487 if (!rtMessageName(nh->nlmsg_type)) {
488 SLOGD("Unexpected netlink message type %d\n", nh->nlmsg_type);
489 continue;
490 }
491
492 if (nh->nlmsg_type == RTM_NEWLINK) {
493 if (parseIfInfoMessage(nh))
494 return true;
495
496 } else if (nh->nlmsg_type == QLOG_NL_EVENT) {
497 if (parseUlogPacketMessage(nh))
498 return true;
499
500 } else if (nh->nlmsg_type == RTM_NEWADDR ||
501 nh->nlmsg_type == RTM_DELADDR) {
502 if (parseIfAddrMessage(nh))
503 return true;
504
505 } else if (nh->nlmsg_type == RTM_NEWROUTE ||
506 nh->nlmsg_type == RTM_DELROUTE) {
507 if (parseRtMessage(nh))
508 return true;
509
510 } else if (nh->nlmsg_type == RTM_NEWNDUSEROPT) {
511 if (parseNdUserOptMessage(nh))
512 return true;
513
514 }
515 }
516
517 return false;
518 }
519
520 /* If the string between 'str' and 'end' begins with 'prefixlen' characters
521 * from the 'prefix' array, then return 'str + prefixlen', otherwise return
522 * NULL.
523 */
524 static const char*
has_prefix(const char * str,const char * end,const char * prefix,size_t prefixlen)525 has_prefix(const char* str, const char* end, const char* prefix, size_t prefixlen)
526 {
527 if ((end-str) >= (ptrdiff_t)prefixlen && !memcmp(str, prefix, prefixlen))
528 return str + prefixlen;
529 else
530 return NULL;
531 }
532
533 /* Same as strlen(x) for constant string literals ONLY */
534 #define CONST_STRLEN(x) (sizeof(x)-1)
535
536 /* Convenience macro to call has_prefix with a constant string literal */
537 #define HAS_CONST_PREFIX(str,end,prefix) has_prefix((str),(end),prefix,CONST_STRLEN(prefix))
538
539
540 /*
541 * Parse an ASCII-formatted message from a NETLINK_KOBJECT_UEVENT
542 * netlink socket.
543 */
parseAsciiNetlinkMessage(char * buffer,int size)544 bool NetlinkEvent::parseAsciiNetlinkMessage(char *buffer, int size) {
545 const char *s = buffer;
546 const char *end;
547 int param_idx = 0;
548 int first = 1;
549
550 if (size == 0)
551 return false;
552
553 /* Ensure the buffer is zero-terminated, the code below depends on this */
554 buffer[size-1] = '\0';
555
556 end = s + size;
557 while (s < end) {
558 if (first) {
559 const char *p;
560 /* buffer is 0-terminated, no need to check p < end */
561 for (p = s; *p != '@'; p++) {
562 if (!*p) { /* no '@', should not happen */
563 return false;
564 }
565 }
566 mPath = strdup(p+1);
567 first = 0;
568 } else {
569 const char* a;
570 if ((a = HAS_CONST_PREFIX(s, end, "ACTION=")) != NULL) {
571 if (!strcmp(a, "add"))
572 mAction = NlActionAdd;
573 else if (!strcmp(a, "remove"))
574 mAction = NlActionRemove;
575 else if (!strcmp(a, "change"))
576 mAction = NlActionChange;
577 } else if ((a = HAS_CONST_PREFIX(s, end, "SEQNUM=")) != NULL) {
578 mSeq = atoi(a);
579 } else if ((a = HAS_CONST_PREFIX(s, end, "SUBSYSTEM=")) != NULL) {
580 mSubsystem = strdup(a);
581 } else if (param_idx < NL_PARAMS_MAX) {
582 mParams[param_idx++] = strdup(s);
583 }
584 }
585 s += strlen(s) + 1;
586 }
587 return true;
588 }
589
decode(char * buffer,int size,int format)590 bool NetlinkEvent::decode(char *buffer, int size, int format) {
591 if (format == NetlinkListener::NETLINK_FORMAT_BINARY) {
592 return parseBinaryNetlinkMessage(buffer, size);
593 } else {
594 return parseAsciiNetlinkMessage(buffer, size);
595 }
596 }
597
findParam(const char * paramName)598 const char *NetlinkEvent::findParam(const char *paramName) {
599 size_t len = strlen(paramName);
600 for (int i = 0; i < NL_PARAMS_MAX && mParams[i] != NULL; ++i) {
601 const char *ptr = mParams[i] + len;
602 if (!strncmp(mParams[i], paramName, len) && *ptr == '=')
603 return ++ptr;
604 }
605
606 SLOGE("NetlinkEvent::FindParam(): Parameter '%s' not found", paramName);
607 return NULL;
608 }
609