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 <linux/if.h> 27 #include <linux/netfilter/nfnetlink.h> 28 #include <linux/netfilter_ipv4/ipt_ULOG.h> 29 /* From kernel's net/netfilter/xt_quota2.c */ 30 const int QLOG_NL_EVENT = 112; 31 32 #include <linux/netlink.h> 33 #include <linux/rtnetlink.h> 34 35 const int NetlinkEvent::NlActionUnknown = 0; 36 const int NetlinkEvent::NlActionAdd = 1; 37 const int NetlinkEvent::NlActionRemove = 2; 38 const int NetlinkEvent::NlActionChange = 3; 39 const int NetlinkEvent::NlActionLinkUp = 4; 40 const int NetlinkEvent::NlActionLinkDown = 5; 41 42 NetlinkEvent::NetlinkEvent() { 43 mAction = NlActionUnknown; 44 memset(mParams, 0, sizeof(mParams)); 45 mPath = NULL; 46 mSubsystem = NULL; 47 } 48 49 NetlinkEvent::~NetlinkEvent() { 50 int i; 51 if (mPath) 52 free(mPath); 53 if (mSubsystem) 54 free(mSubsystem); 55 for (i = 0; i < NL_PARAMS_MAX; i++) { 56 if (!mParams[i]) 57 break; 58 free(mParams[i]); 59 } 60 } 61 62 void NetlinkEvent::dump() { 63 int i; 64 65 for (i = 0; i < NL_PARAMS_MAX; i++) { 66 if (!mParams[i]) 67 break; 68 SLOGD("NL param '%s'\n", mParams[i]); 69 } 70 } 71 72 /* 73 * Parse an binary message from a NETLINK_ROUTE netlink socket. 74 */ 75 bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) { 76 size_t sz = size; 77 const struct nlmsghdr *nh = (struct nlmsghdr *) buffer; 78 79 while (NLMSG_OK(nh, sz) && (nh->nlmsg_type != NLMSG_DONE)) { 80 81 if (nh->nlmsg_type == RTM_NEWLINK) { 82 int len = nh->nlmsg_len - sizeof(*nh); 83 struct ifinfomsg *ifi; 84 85 if (sizeof(*ifi) > (size_t) len) { 86 SLOGE("Got a short RTM_NEWLINK message\n"); 87 continue; 88 } 89 90 ifi = (ifinfomsg *)NLMSG_DATA(nh); 91 if ((ifi->ifi_flags & IFF_LOOPBACK) != 0) { 92 continue; 93 } 94 95 struct rtattr *rta = (struct rtattr *) 96 ((char *) ifi + NLMSG_ALIGN(sizeof(*ifi))); 97 len = NLMSG_PAYLOAD(nh, sizeof(*ifi)); 98 99 while(RTA_OK(rta, len)) { 100 switch(rta->rta_type) { 101 case IFLA_IFNAME: 102 char buffer[16 + IFNAMSIZ]; 103 snprintf(buffer, sizeof(buffer), "INTERFACE=%s", 104 (char *) RTA_DATA(rta)); 105 mParams[0] = strdup(buffer); 106 mAction = (ifi->ifi_flags & IFF_LOWER_UP) ? 107 NlActionLinkUp : NlActionLinkDown; 108 mSubsystem = strdup("net"); 109 break; 110 } 111 112 rta = RTA_NEXT(rta, len); 113 } 114 115 } else if (nh->nlmsg_type == QLOG_NL_EVENT) { 116 char *devname; 117 ulog_packet_msg_t *pm; 118 size_t len = nh->nlmsg_len - sizeof(*nh); 119 if (sizeof(*pm) > len) { 120 SLOGE("Got a short QLOG message\n"); 121 continue; 122 } 123 pm = (ulog_packet_msg_t *)NLMSG_DATA(nh); 124 devname = pm->indev_name[0] ? pm->indev_name : pm->outdev_name; 125 asprintf(&mParams[0], "ALERT_NAME=%s", pm->prefix); 126 asprintf(&mParams[1], "INTERFACE=%s", devname); 127 mSubsystem = strdup("qlog"); 128 mAction = NlActionChange; 129 130 } else { 131 SLOGD("Unexpected netlink message. type=0x%x\n", nh->nlmsg_type); 132 } 133 nh = NLMSG_NEXT(nh, size); 134 } 135 136 return true; 137 } 138 139 /* If the string between 'str' and 'end' begins with 'prefixlen' characters 140 * from the 'prefix' array, then return 'str + prefixlen', otherwise return 141 * NULL. 142 */ 143 static const char* 144 has_prefix(const char* str, const char* end, const char* prefix, size_t prefixlen) 145 { 146 if ((end-str) >= (ptrdiff_t)prefixlen && !memcmp(str, prefix, prefixlen)) 147 return str + prefixlen; 148 else 149 return NULL; 150 } 151 152 /* Same as strlen(x) for constant string literals ONLY */ 153 #define CONST_STRLEN(x) (sizeof(x)-1) 154 155 /* Convenience macro to call has_prefix with a constant string literal */ 156 #define HAS_CONST_PREFIX(str,end,prefix) has_prefix((str),(end),prefix,CONST_STRLEN(prefix)) 157 158 159 /* 160 * Parse an ASCII-formatted message from a NETLINK_KOBJECT_UEVENT 161 * netlink socket. 162 */ 163 bool NetlinkEvent::parseAsciiNetlinkMessage(char *buffer, int size) { 164 const char *s = buffer; 165 const char *end; 166 int param_idx = 0; 167 int i; 168 int first = 1; 169 170 if (size == 0) 171 return false; 172 173 /* Ensure the buffer is zero-terminated, the code below depends on this */ 174 buffer[size-1] = '\0'; 175 176 end = s + size; 177 while (s < end) { 178 if (first) { 179 const char *p; 180 /* buffer is 0-terminated, no need to check p < end */ 181 for (p = s; *p != '@'; p++) { 182 if (!*p) { /* no '@', should not happen */ 183 return false; 184 } 185 } 186 mPath = strdup(p+1); 187 first = 0; 188 } else { 189 const char* a; 190 if ((a = HAS_CONST_PREFIX(s, end, "ACTION=")) != NULL) { 191 if (!strcmp(a, "add")) 192 mAction = NlActionAdd; 193 else if (!strcmp(a, "remove")) 194 mAction = NlActionRemove; 195 else if (!strcmp(a, "change")) 196 mAction = NlActionChange; 197 } else if ((a = HAS_CONST_PREFIX(s, end, "SEQNUM=")) != NULL) { 198 mSeq = atoi(a); 199 } else if ((a = HAS_CONST_PREFIX(s, end, "SUBSYSTEM=")) != NULL) { 200 mSubsystem = strdup(a); 201 } else if (param_idx < NL_PARAMS_MAX) { 202 mParams[param_idx++] = strdup(s); 203 } 204 } 205 s += strlen(s) + 1; 206 } 207 return true; 208 } 209 210 bool NetlinkEvent::decode(char *buffer, int size, int format) { 211 if (format == NetlinkListener::NETLINK_FORMAT_BINARY) { 212 return parseBinaryNetlinkMessage(buffer, size); 213 } else { 214 return parseAsciiNetlinkMessage(buffer, size); 215 } 216 } 217 218 const char *NetlinkEvent::findParam(const char *paramName) { 219 size_t len = strlen(paramName); 220 for (int i = 0; i < NL_PARAMS_MAX && mParams[i] != NULL; ++i) { 221 const char *ptr = mParams[i] + len; 222 if (!strncmp(mParams[i], paramName, len) && *ptr == '=') 223 return ++ptr; 224 } 225 226 SLOGE("NetlinkEvent::FindParam(): Parameter '%s' not found", paramName); 227 return NULL; 228 } 229
