| /* | 
 |  * Copyright (C) 2008 The Android Open Source Project | 
 |  * | 
 |  * Licensed under the Apache License, Version 2.0 (the "License"); | 
 |  * you may not use this file except in compliance with the License. | 
 |  * You may obtain a copy of the License at | 
 |  * | 
 |  *      http://www.apache.org/licenses/LICENSE-2.0 | 
 |  * | 
 |  * Unless required by applicable law or agreed to in writing, software | 
 |  * distributed under the License is distributed on an "AS IS" BASIS, | 
 |  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | 
 |  * See the License for the specific language governing permissions and | 
 |  * limitations under the License. | 
 |  */ | 
 |  | 
 | #define LOG_TAG "NetlinkEvent" | 
 |  | 
 | #include <arpa/inet.h> | 
 | #include <linux/if.h> | 
 | #include <linux/if_addr.h> | 
 | #include <linux/if_link.h> | 
 | #include <linux/netfilter/nfnetlink.h> | 
 | #include <linux/netfilter/nfnetlink_log.h> | 
 | #include <linux/netfilter_ipv4/ipt_ULOG.h> | 
 | #include <linux/netlink.h> | 
 | #include <linux/rtnetlink.h> | 
 | #include <net/if.h> | 
 | #include <netinet/in.h> | 
 | #include <netinet/icmp6.h> | 
 | #include <netlink/attr.h> | 
 | #include <netlink/genl/genl.h> | 
 | #include <netlink/handlers.h> | 
 | #include <netlink/msg.h> | 
 | #include <stdlib.h> | 
 | #include <string.h> | 
 | #include <sys/socket.h> | 
 | #include <sys/types.h> | 
 |  | 
 | /* From kernel's net/netfilter/xt_quota2.c */ | 
 | const int LOCAL_QLOG_NL_EVENT = 112; | 
 | const int LOCAL_NFLOG_PACKET = NFNL_SUBSYS_ULOG << 8 | NFULNL_MSG_PACKET; | 
 |  | 
 | #include <log/log.h> | 
 | #include <sysutils/NetlinkEvent.h> | 
 |  | 
 | NetlinkEvent::NetlinkEvent() { | 
 |     mAction = Action::kUnknown; | 
 |     memset(mParams, 0, sizeof(mParams)); | 
 |     mPath = NULL; | 
 |     mSubsystem = NULL; | 
 | } | 
 |  | 
 | NetlinkEvent::~NetlinkEvent() { | 
 |     int i; | 
 |     if (mPath) | 
 |         free(mPath); | 
 |     if (mSubsystem) | 
 |         free(mSubsystem); | 
 |     for (i = 0; i < NL_PARAMS_MAX; i++) { | 
 |         if (!mParams[i]) | 
 |             break; | 
 |         free(mParams[i]); | 
 |     } | 
 | } | 
 |  | 
 | void NetlinkEvent::dump() { | 
 |     int i; | 
 |  | 
 |     for (i = 0; i < NL_PARAMS_MAX; i++) { | 
 |         if (!mParams[i]) | 
 |             break; | 
 |         SLOGD("NL param '%s'\n", mParams[i]); | 
 |     } | 
 | } | 
 |  | 
 | /* | 
 |  * Returns the message name for a message in the NETLINK_ROUTE family, or NULL | 
 |  * if parsing that message is not supported. | 
 |  */ | 
 | static const char *rtMessageName(int type) { | 
 | #define NL_EVENT_RTM_NAME(rtm) case rtm: return #rtm; | 
 |     switch (type) { | 
 |         NL_EVENT_RTM_NAME(RTM_NEWLINK); | 
 |         NL_EVENT_RTM_NAME(RTM_DELLINK); | 
 |         NL_EVENT_RTM_NAME(RTM_NEWADDR); | 
 |         NL_EVENT_RTM_NAME(RTM_DELADDR); | 
 |         NL_EVENT_RTM_NAME(RTM_NEWROUTE); | 
 |         NL_EVENT_RTM_NAME(RTM_DELROUTE); | 
 |         NL_EVENT_RTM_NAME(RTM_NEWNDUSEROPT); | 
 |         NL_EVENT_RTM_NAME(LOCAL_QLOG_NL_EVENT); | 
 |         NL_EVENT_RTM_NAME(LOCAL_NFLOG_PACKET); | 
 |         default: | 
 |             return NULL; | 
 |     } | 
 | #undef NL_EVENT_RTM_NAME | 
 | } | 
 |  | 
 | /* | 
 |  * Checks that a binary NETLINK_ROUTE message is long enough for a payload of | 
 |  * size bytes. | 
 |  */ | 
 | static bool checkRtNetlinkLength(const struct nlmsghdr *nh, size_t size) { | 
 |     if (nh->nlmsg_len < NLMSG_LENGTH(size)) { | 
 |         SLOGE("Got a short %s message\n", rtMessageName(nh->nlmsg_type)); | 
 |         return false; | 
 |     } | 
 |     return true; | 
 | } | 
 |  | 
 | /* | 
 |  * Utility function to log errors. | 
 |  */ | 
 | static bool maybeLogDuplicateAttribute(bool isDup, | 
 |                                        const char *attributeName, | 
 |                                        const char *messageName) { | 
 |     if (isDup) { | 
 |         SLOGE("Multiple %s attributes in %s, ignoring\n", attributeName, messageName); | 
 |         return true; | 
 |     } | 
 |     return false; | 
 | } | 
 |  | 
 | /* | 
 |  * Parse a RTM_NEWLINK message. | 
 |  */ | 
 | bool NetlinkEvent::parseIfInfoMessage(const struct nlmsghdr *nh) { | 
 |     struct ifinfomsg *ifi = (struct ifinfomsg *) NLMSG_DATA(nh); | 
 |     if (!checkRtNetlinkLength(nh, sizeof(*ifi))) | 
 |         return false; | 
 |  | 
 |     if ((ifi->ifi_flags & IFF_LOOPBACK) != 0) { | 
 |         return false; | 
 |     } | 
 |  | 
 |     int len = IFLA_PAYLOAD(nh); | 
 |     struct rtattr *rta; | 
 |     for (rta = IFLA_RTA(ifi); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) { | 
 |         switch(rta->rta_type) { | 
 |             case IFLA_IFNAME: | 
 |                 asprintf(&mParams[0], "INTERFACE=%s", (char *) RTA_DATA(rta)); | 
 |                 mAction = (ifi->ifi_flags & IFF_LOWER_UP) ? Action::kLinkUp : | 
 |                                                             Action::kLinkDown; | 
 |                 mSubsystem = strdup("net"); | 
 |                 return true; | 
 |         } | 
 |     } | 
 |  | 
 |     return false; | 
 | } | 
 |  | 
 | /* | 
 |  * Parse a RTM_NEWADDR or RTM_DELADDR message. | 
 |  */ | 
 | bool NetlinkEvent::parseIfAddrMessage(const struct nlmsghdr *nh) { | 
 |     struct ifaddrmsg *ifaddr = (struct ifaddrmsg *) NLMSG_DATA(nh); | 
 |     struct ifa_cacheinfo *cacheinfo = NULL; | 
 |     char addrstr[INET6_ADDRSTRLEN] = ""; | 
 |     char ifname[IFNAMSIZ] = ""; | 
 |  | 
 |     if (!checkRtNetlinkLength(nh, sizeof(*ifaddr))) | 
 |         return false; | 
 |  | 
 |     // Sanity check. | 
 |     int type = nh->nlmsg_type; | 
 |     if (type != RTM_NEWADDR && type != RTM_DELADDR) { | 
 |         SLOGE("parseIfAddrMessage on incorrect message type 0x%x\n", type); | 
 |         return false; | 
 |     } | 
 |  | 
 |     // For log messages. | 
 |     const char *msgtype = rtMessageName(type); | 
 |  | 
 |     struct rtattr *rta; | 
 |     int len = IFA_PAYLOAD(nh); | 
 |     for (rta = IFA_RTA(ifaddr); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) { | 
 |         if (rta->rta_type == IFA_ADDRESS) { | 
 |             // Only look at the first address, because we only support notifying | 
 |             // one change at a time. | 
 |             if (maybeLogDuplicateAttribute(*addrstr != '\0', "IFA_ADDRESS", msgtype)) | 
 |                 continue; | 
 |  | 
 |             // Convert the IP address to a string. | 
 |             if (ifaddr->ifa_family == AF_INET) { | 
 |                 struct in_addr *addr4 = (struct in_addr *) RTA_DATA(rta); | 
 |                 if (RTA_PAYLOAD(rta) < sizeof(*addr4)) { | 
 |                     SLOGE("Short IPv4 address (%zu bytes) in %s", | 
 |                           RTA_PAYLOAD(rta), msgtype); | 
 |                     continue; | 
 |                 } | 
 |                 inet_ntop(AF_INET, addr4, addrstr, sizeof(addrstr)); | 
 |             } else if (ifaddr->ifa_family == AF_INET6) { | 
 |                 struct in6_addr *addr6 = (struct in6_addr *) RTA_DATA(rta); | 
 |                 if (RTA_PAYLOAD(rta) < sizeof(*addr6)) { | 
 |                     SLOGE("Short IPv6 address (%zu bytes) in %s", | 
 |                           RTA_PAYLOAD(rta), msgtype); | 
 |                     continue; | 
 |                 } | 
 |                 inet_ntop(AF_INET6, addr6, addrstr, sizeof(addrstr)); | 
 |             } else { | 
 |                 SLOGE("Unknown address family %d\n", ifaddr->ifa_family); | 
 |                 continue; | 
 |             } | 
 |  | 
 |             // Find the interface name. | 
 |             if (!if_indextoname(ifaddr->ifa_index, ifname)) { | 
 |                 SLOGD("Unknown ifindex %d in %s", ifaddr->ifa_index, msgtype); | 
 |             } | 
 |  | 
 |         } else if (rta->rta_type == IFA_CACHEINFO) { | 
 |             // Address lifetime information. | 
 |             if (maybeLogDuplicateAttribute(cacheinfo, "IFA_CACHEINFO", msgtype)) | 
 |                 continue; | 
 |  | 
 |             if (RTA_PAYLOAD(rta) < sizeof(*cacheinfo)) { | 
 |                 SLOGE("Short IFA_CACHEINFO (%zu vs. %zu bytes) in %s", | 
 |                       RTA_PAYLOAD(rta), sizeof(cacheinfo), msgtype); | 
 |                 continue; | 
 |             } | 
 |  | 
 |             cacheinfo = (struct ifa_cacheinfo *) RTA_DATA(rta); | 
 |         } | 
 |     } | 
 |  | 
 |     if (addrstr[0] == '\0') { | 
 |         SLOGE("No IFA_ADDRESS in %s\n", msgtype); | 
 |         return false; | 
 |     } | 
 |  | 
 |     // Fill in netlink event information. | 
 |     mAction = (type == RTM_NEWADDR) ? Action::kAddressUpdated : | 
 |                                       Action::kAddressRemoved; | 
 |     mSubsystem = strdup("net"); | 
 |     asprintf(&mParams[0], "ADDRESS=%s/%d", addrstr, ifaddr->ifa_prefixlen); | 
 |     asprintf(&mParams[1], "INTERFACE=%s", ifname); | 
 |     asprintf(&mParams[2], "FLAGS=%u", ifaddr->ifa_flags); | 
 |     asprintf(&mParams[3], "SCOPE=%u", ifaddr->ifa_scope); | 
 |  | 
 |     if (cacheinfo) { | 
 |         asprintf(&mParams[4], "PREFERRED=%u", cacheinfo->ifa_prefered); | 
 |         asprintf(&mParams[5], "VALID=%u", cacheinfo->ifa_valid); | 
 |         asprintf(&mParams[6], "CSTAMP=%u", cacheinfo->cstamp); | 
 |         asprintf(&mParams[7], "TSTAMP=%u", cacheinfo->tstamp); | 
 |     } | 
 |  | 
 |     return true; | 
 | } | 
 |  | 
 | /* | 
 |  * Parse a QLOG_NL_EVENT message. | 
 |  */ | 
 | bool NetlinkEvent::parseUlogPacketMessage(const struct nlmsghdr *nh) { | 
 |     const char *devname; | 
 |     ulog_packet_msg_t *pm = (ulog_packet_msg_t *) NLMSG_DATA(nh); | 
 |     if (!checkRtNetlinkLength(nh, sizeof(*pm))) | 
 |         return false; | 
 |  | 
 |     devname = pm->indev_name[0] ? pm->indev_name : pm->outdev_name; | 
 |     asprintf(&mParams[0], "ALERT_NAME=%s", pm->prefix); | 
 |     asprintf(&mParams[1], "INTERFACE=%s", devname); | 
 |     mSubsystem = strdup("qlog"); | 
 |     mAction = Action::kChange; | 
 |     return true; | 
 | } | 
 |  | 
 | /* | 
 |  * Parse a LOCAL_NFLOG_PACKET message. | 
 |  */ | 
 | bool NetlinkEvent::parseNfPacketMessage(struct nlmsghdr *nh) { | 
 |     int uid = -1; | 
 |     int len = 0; | 
 |     char* raw = NULL; | 
 |  | 
 |     struct nlattr *uid_attr = nlmsg_find_attr(nh, sizeof(struct genlmsghdr), NFULA_UID); | 
 |     if (uid_attr) { | 
 |         uid = ntohl(nla_get_u32(uid_attr)); | 
 |     } | 
 |  | 
 |     struct nlattr *payload = nlmsg_find_attr(nh, sizeof(struct genlmsghdr), NFULA_PAYLOAD); | 
 |     if (payload) { | 
 |         /* First 256 bytes is plenty */ | 
 |         len = nla_len(payload); | 
 |         if (len > 256) len = 256; | 
 |         raw = (char*) nla_data(payload); | 
 |     } | 
 |  | 
 |     char* hex = (char*) calloc(1, 5 + (len * 2)); | 
 |     strcpy(hex, "HEX="); | 
 |     for (int i = 0; i < len; i++) { | 
 |         hex[4 + (i * 2)] = "0123456789abcdef"[(raw[i] >> 4) & 0xf]; | 
 |         hex[5 + (i * 2)] = "0123456789abcdef"[raw[i] & 0xf]; | 
 |     } | 
 |  | 
 |     asprintf(&mParams[0], "UID=%d", uid); | 
 |     mParams[1] = hex; | 
 |     mSubsystem = strdup("strict"); | 
 |     mAction = Action::kChange; | 
 |     return true; | 
 | } | 
 |  | 
 | /* | 
 |  * Parse a RTM_NEWROUTE or RTM_DELROUTE message. | 
 |  */ | 
 | bool NetlinkEvent::parseRtMessage(const struct nlmsghdr *nh) { | 
 |     uint8_t type = nh->nlmsg_type; | 
 |     const char *msgname = rtMessageName(type); | 
 |  | 
 |     // Sanity check. | 
 |     if (type != RTM_NEWROUTE && type != RTM_DELROUTE) { | 
 |         SLOGE("%s: incorrect message type %d (%s)\n", __func__, type, msgname); | 
 |         return false; | 
 |     } | 
 |  | 
 |     struct rtmsg *rtm = (struct rtmsg *) NLMSG_DATA(nh); | 
 |     if (!checkRtNetlinkLength(nh, sizeof(*rtm))) | 
 |         return false; | 
 |  | 
 |     if (// Ignore static routes we've set up ourselves. | 
 |         (rtm->rtm_protocol != RTPROT_KERNEL && | 
 |          rtm->rtm_protocol != RTPROT_RA) || | 
 |         // We're only interested in global unicast routes. | 
 |         (rtm->rtm_scope != RT_SCOPE_UNIVERSE) || | 
 |         (rtm->rtm_type != RTN_UNICAST) || | 
 |         // We don't support source routing. | 
 |         (rtm->rtm_src_len != 0) || | 
 |         // Cloned routes aren't real routes. | 
 |         (rtm->rtm_flags & RTM_F_CLONED)) { | 
 |         return false; | 
 |     } | 
 |  | 
 |     int family = rtm->rtm_family; | 
 |     int prefixLength = rtm->rtm_dst_len; | 
 |  | 
 |     // Currently we only support: destination, (one) next hop, ifindex. | 
 |     char dst[INET6_ADDRSTRLEN] = ""; | 
 |     char gw[INET6_ADDRSTRLEN] = ""; | 
 |     char dev[IFNAMSIZ] = ""; | 
 |  | 
 |     size_t len = RTM_PAYLOAD(nh); | 
 |     struct rtattr *rta; | 
 |     for (rta = RTM_RTA(rtm); RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) { | 
 |         switch (rta->rta_type) { | 
 |             case RTA_DST: | 
 |                 if (maybeLogDuplicateAttribute(*dst, "RTA_DST", msgname)) | 
 |                     continue; | 
 |                 if (!inet_ntop(family, RTA_DATA(rta), dst, sizeof(dst))) | 
 |                     return false; | 
 |                 continue; | 
 |             case RTA_GATEWAY: | 
 |                 if (maybeLogDuplicateAttribute(*gw, "RTA_GATEWAY", msgname)) | 
 |                     continue; | 
 |                 if (!inet_ntop(family, RTA_DATA(rta), gw, sizeof(gw))) | 
 |                     return false; | 
 |                 continue; | 
 |             case RTA_OIF: | 
 |                 if (maybeLogDuplicateAttribute(*dev, "RTA_OIF", msgname)) | 
 |                     continue; | 
 |                 if (!if_indextoname(* (int *) RTA_DATA(rta), dev)) | 
 |                     return false; | 
 |             default: | 
 |                 continue; | 
 |         } | 
 |     } | 
 |  | 
 |    // If there's no RTA_DST attribute, then: | 
 |    // - If the prefix length is zero, it's the default route. | 
 |    // - If the prefix length is nonzero, there's something we don't understand. | 
 |    //   Ignore the event. | 
 |    if (!*dst && !prefixLength) { | 
 |         if (family == AF_INET) { | 
 |             strncpy(dst, "0.0.0.0", sizeof(dst)); | 
 |         } else if (family == AF_INET6) { | 
 |             strncpy(dst, "::", sizeof(dst)); | 
 |         } | 
 |     } | 
 |  | 
 |     // A useful route must have a destination and at least either a gateway or | 
 |     // an interface. | 
 |     if (!*dst || (!*gw && !*dev)) | 
 |         return false; | 
 |  | 
 |     // Fill in netlink event information. | 
 |     mAction = (type == RTM_NEWROUTE) ? Action::kRouteUpdated : | 
 |                                        Action::kRouteRemoved; | 
 |     mSubsystem = strdup("net"); | 
 |     asprintf(&mParams[0], "ROUTE=%s/%d", dst, prefixLength); | 
 |     asprintf(&mParams[1], "GATEWAY=%s", (*gw) ? gw : ""); | 
 |     asprintf(&mParams[2], "INTERFACE=%s", (*dev) ? dev : ""); | 
 |  | 
 |     return true; | 
 | } | 
 |  | 
 | /* | 
 |  * Parse a RTM_NEWNDUSEROPT message. | 
 |  */ | 
 | bool NetlinkEvent::parseNdUserOptMessage(const struct nlmsghdr *nh) { | 
 |     struct nduseroptmsg *msg = (struct nduseroptmsg *) NLMSG_DATA(nh); | 
 |     if (!checkRtNetlinkLength(nh, sizeof(*msg))) | 
 |         return false; | 
 |  | 
 |     // Check the length is valid. | 
 |     int len = NLMSG_PAYLOAD(nh, sizeof(*msg)); | 
 |     if (msg->nduseropt_opts_len > len) { | 
 |         SLOGE("RTM_NEWNDUSEROPT invalid length %d > %d\n", | 
 |               msg->nduseropt_opts_len, len); | 
 |         return false; | 
 |     } | 
 |     len = msg->nduseropt_opts_len; | 
 |  | 
 |     // Check address family and packet type. | 
 |     if (msg->nduseropt_family != AF_INET6) { | 
 |         SLOGE("RTM_NEWNDUSEROPT message for unknown family %d\n", | 
 |               msg->nduseropt_family); | 
 |         return false; | 
 |     } | 
 |  | 
 |     if (msg->nduseropt_icmp_type != ND_ROUTER_ADVERT || | 
 |         msg->nduseropt_icmp_code != 0) { | 
 |         SLOGE("RTM_NEWNDUSEROPT message for unknown ICMPv6 type/code %d/%d\n", | 
 |               msg->nduseropt_icmp_type, msg->nduseropt_icmp_code); | 
 |         return false; | 
 |     } | 
 |  | 
 |     // Find the interface name. | 
 |     char ifname[IFNAMSIZ]; | 
 |     if (!if_indextoname(msg->nduseropt_ifindex, ifname)) { | 
 |         SLOGE("RTM_NEWNDUSEROPT on unknown ifindex %d\n", | 
 |               msg->nduseropt_ifindex); | 
 |         return false; | 
 |     } | 
 |  | 
 |     // The kernel sends a separate netlink message for each ND option in the RA. | 
 |     // So only parse the first ND option in the message. | 
 |     struct nd_opt_hdr *opthdr = (struct nd_opt_hdr *) (msg + 1); | 
 |  | 
 |     // The length is in multiples of 8 octets. | 
 |     uint16_t optlen = opthdr->nd_opt_len; | 
 |     if (optlen * 8 > len) { | 
 |         SLOGE("Invalid option length %d > %d for ND option %d\n", | 
 |               optlen * 8, len, opthdr->nd_opt_type); | 
 |         return false; | 
 |     } | 
 |  | 
 |     if (opthdr->nd_opt_type == ND_OPT_RDNSS) { | 
 |         // DNS Servers (RFC 6106). | 
 |         // Each address takes up 2*8 octets, and the header takes up 8 octets. | 
 |         // So for a valid option with one or more addresses, optlen must be | 
 |         // odd and greater than 1. | 
 |         if ((optlen < 3) || !(optlen & 0x1)) { | 
 |             SLOGE("Invalid optlen %d for RDNSS option\n", optlen); | 
 |             return false; | 
 |         } | 
 |         const int numaddrs = (optlen - 1) / 2; | 
 |  | 
 |         // Find the lifetime. | 
 |         struct nd_opt_rdnss *rndss_opt = (struct nd_opt_rdnss *) opthdr; | 
 |         const uint32_t lifetime = ntohl(rndss_opt->nd_opt_rdnss_lifetime); | 
 |  | 
 |         // Construct "SERVERS=<comma-separated string of DNS addresses>". | 
 |         static const char kServerTag[] = "SERVERS="; | 
 |         static const size_t kTagLength = strlen(kServerTag); | 
 |         // Reserve sufficient space for an IPv6 link-local address: all but the | 
 |         // last address are followed by ','; the last is followed by '\0'. | 
 |         static const size_t kMaxSingleAddressLength = | 
 |                 INET6_ADDRSTRLEN + strlen("%") + IFNAMSIZ + strlen(","); | 
 |         const size_t bufsize = kTagLength + numaddrs * kMaxSingleAddressLength; | 
 |         char *buf = (char *) malloc(bufsize); | 
 |         if (!buf) { | 
 |             SLOGE("RDNSS option: out of memory\n"); | 
 |             return false; | 
 |         } | 
 |         strcpy(buf, kServerTag); | 
 |         size_t pos = kTagLength; | 
 |  | 
 |         struct in6_addr *addrs = (struct in6_addr *) (rndss_opt + 1); | 
 |         for (int i = 0; i < numaddrs; i++) { | 
 |             if (i > 0) { | 
 |                 buf[pos++] = ','; | 
 |             } | 
 |             inet_ntop(AF_INET6, addrs + i, buf + pos, bufsize - pos); | 
 |             pos += strlen(buf + pos); | 
 |             if (IN6_IS_ADDR_LINKLOCAL(addrs + i)) { | 
 |                 buf[pos++] = '%'; | 
 |                 pos += strlcpy(buf + pos, ifname, bufsize - pos); | 
 |             } | 
 |         } | 
 |         buf[pos] = '\0'; | 
 |  | 
 |         mAction = Action::kRdnss; | 
 |         mSubsystem = strdup("net"); | 
 |         asprintf(&mParams[0], "INTERFACE=%s", ifname); | 
 |         asprintf(&mParams[1], "LIFETIME=%u", lifetime); | 
 |         mParams[2] = buf; | 
 |     } else { | 
 |         SLOGD("Unknown ND option type %d\n", opthdr->nd_opt_type); | 
 |         return false; | 
 |     } | 
 |  | 
 |     return true; | 
 | } | 
 |  | 
 | /* | 
 |  * Parse a binary message from a NETLINK_ROUTE netlink socket. | 
 |  * | 
 |  * Note that this function can only parse one message, because the message's | 
 |  * content has to be stored in the class's member variables (mAction, | 
 |  * mSubsystem, etc.). Invalid or unrecognized messages are skipped, but if | 
 |  * there are multiple valid messages in the buffer, only the first one will be | 
 |  * returned. | 
 |  * | 
 |  * TODO: consider only ever looking at the first message. | 
 |  */ | 
 | bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) { | 
 |     struct nlmsghdr *nh; | 
 |  | 
 |     for (nh = (struct nlmsghdr *) buffer; | 
 |          NLMSG_OK(nh, (unsigned) size) && (nh->nlmsg_type != NLMSG_DONE); | 
 |          nh = NLMSG_NEXT(nh, size)) { | 
 |  | 
 |         if (!rtMessageName(nh->nlmsg_type)) { | 
 |             SLOGD("Unexpected netlink message type %d\n", nh->nlmsg_type); | 
 |             continue; | 
 |         } | 
 |  | 
 |         if (nh->nlmsg_type == RTM_NEWLINK) { | 
 |             if (parseIfInfoMessage(nh)) | 
 |                 return true; | 
 |  | 
 |         } else if (nh->nlmsg_type == LOCAL_QLOG_NL_EVENT) { | 
 |             if (parseUlogPacketMessage(nh)) | 
 |                 return true; | 
 |  | 
 |         } else if (nh->nlmsg_type == RTM_NEWADDR || | 
 |                    nh->nlmsg_type == RTM_DELADDR) { | 
 |             if (parseIfAddrMessage(nh)) | 
 |                 return true; | 
 |  | 
 |         } else if (nh->nlmsg_type == RTM_NEWROUTE || | 
 |                    nh->nlmsg_type == RTM_DELROUTE) { | 
 |             if (parseRtMessage(nh)) | 
 |                 return true; | 
 |  | 
 |         } else if (nh->nlmsg_type == RTM_NEWNDUSEROPT) { | 
 |             if (parseNdUserOptMessage(nh)) | 
 |                 return true; | 
 |  | 
 |         } else if (nh->nlmsg_type == LOCAL_NFLOG_PACKET) { | 
 |             if (parseNfPacketMessage(nh)) | 
 |                 return true; | 
 |  | 
 |         } | 
 |     } | 
 |  | 
 |     return false; | 
 | } | 
 |  | 
 | /* If the string between 'str' and 'end' begins with 'prefixlen' characters | 
 |  * from the 'prefix' array, then return 'str + prefixlen', otherwise return | 
 |  * NULL. | 
 |  */ | 
 | static const char* | 
 | has_prefix(const char* str, const char* end, const char* prefix, size_t prefixlen) | 
 | { | 
 |     if ((end-str) >= (ptrdiff_t)prefixlen && !memcmp(str, prefix, prefixlen)) | 
 |         return str + prefixlen; | 
 |     else | 
 |         return NULL; | 
 | } | 
 |  | 
 | /* Same as strlen(x) for constant string literals ONLY */ | 
 | #define CONST_STRLEN(x)  (sizeof(x)-1) | 
 |  | 
 | /* Convenience macro to call has_prefix with a constant string literal  */ | 
 | #define HAS_CONST_PREFIX(str,end,prefix)  has_prefix((str),(end),prefix,CONST_STRLEN(prefix)) | 
 |  | 
 |  | 
 | /* | 
 |  * Parse an ASCII-formatted message from a NETLINK_KOBJECT_UEVENT | 
 |  * netlink socket. | 
 |  */ | 
 | bool NetlinkEvent::parseAsciiNetlinkMessage(char *buffer, int size) { | 
 |     const char *s = buffer; | 
 |     const char *end; | 
 |     int param_idx = 0; | 
 |     int first = 1; | 
 |  | 
 |     if (size == 0) | 
 |         return false; | 
 |  | 
 |     /* Ensure the buffer is zero-terminated, the code below depends on this */ | 
 |     buffer[size-1] = '\0'; | 
 |  | 
 |     end = s + size; | 
 |     while (s < end) { | 
 |         if (first) { | 
 |             const char *p; | 
 |             /* buffer is 0-terminated, no need to check p < end */ | 
 |             for (p = s; *p != '@'; p++) { | 
 |                 if (!*p) { /* no '@', should not happen */ | 
 |                     return false; | 
 |                 } | 
 |             } | 
 |             mPath = strdup(p+1); | 
 |             first = 0; | 
 |         } else { | 
 |             const char* a; | 
 |             if ((a = HAS_CONST_PREFIX(s, end, "ACTION=")) != NULL) { | 
 |                 if (!strcmp(a, "add")) | 
 |                     mAction = Action::kAdd; | 
 |                 else if (!strcmp(a, "remove")) | 
 |                     mAction = Action::kRemove; | 
 |                 else if (!strcmp(a, "change")) | 
 |                     mAction = Action::kChange; | 
 |             } else if ((a = HAS_CONST_PREFIX(s, end, "SEQNUM=")) != NULL) { | 
 |                 mSeq = atoi(a); | 
 |             } else if ((a = HAS_CONST_PREFIX(s, end, "SUBSYSTEM=")) != NULL) { | 
 |                 mSubsystem = strdup(a); | 
 |             } else if (param_idx < NL_PARAMS_MAX) { | 
 |                 mParams[param_idx++] = strdup(s); | 
 |             } | 
 |         } | 
 |         s += strlen(s) + 1; | 
 |     } | 
 |     return true; | 
 | } | 
 |  | 
 | bool NetlinkEvent::decode(char *buffer, int size, int format) { | 
 |     if (format == NetlinkListener::NETLINK_FORMAT_BINARY | 
 |             || format == NetlinkListener::NETLINK_FORMAT_BINARY_UNICAST) { | 
 |         return parseBinaryNetlinkMessage(buffer, size); | 
 |     } else { | 
 |         return parseAsciiNetlinkMessage(buffer, size); | 
 |     } | 
 | } | 
 |  | 
 | const char *NetlinkEvent::findParam(const char *paramName) { | 
 |     size_t len = strlen(paramName); | 
 |     for (int i = 0; i < NL_PARAMS_MAX && mParams[i] != NULL; ++i) { | 
 |         const char *ptr = mParams[i] + len; | 
 |         if (!strncmp(mParams[i], paramName, len) && *ptr == '=') | 
 |             return ++ptr; | 
 |     } | 
 |  | 
 |     SLOGE("NetlinkEvent::FindParam(): Parameter '%s' not found", paramName); | 
 |     return NULL; | 
 | } |