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Merge "Support parsing RDNSS ND options from netlink."

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Lorenzo Colitti 2013-11-20 02:22:19 +00:00 committed by Gerrit Code Review
commit cbc32e9f7e
2 changed files with 124 additions and 5 deletions
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4
include/sysutils/NetlinkEvent.h
View file

@ -36,6 +36,7 @@ public:
const static int NlActionLinkUp;
const static int NlActionAddressUpdated;
const static int NlActionAddressRemoved;
const static int NlActionRdnss;
NetlinkEvent();
virtual ~NetlinkEvent();
@ -49,9 +50,10 @@ public:
void dump();
protected:
bool parseIfAddrMessage(int type, struct ifaddrmsg *ifaddr, int rtasize);
bool parseBinaryNetlinkMessage(char *buffer, int size);
bool parseAsciiNetlinkMessage(char *buffer, int size);
bool parseIfAddrMessage(int type, struct ifaddrmsg *ifaddr, int rtasize);
bool parseNdUserOptMessage(struct nduseroptmsg *msg, int optsize);
};
#endif

125
libsysutils/src/NetlinkEvent.cpp
View file

@ -24,6 +24,7 @@
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/icmp6.h>
#include <arpa/inet.h>
#include <net/if.h>
@ -44,6 +45,7 @@ const int NetlinkEvent::NlActionLinkUp = 4;
const int NetlinkEvent::NlActionLinkDown = 5;
const int NetlinkEvent::NlActionAddressUpdated = 6;
const int NetlinkEvent::NlActionAddressRemoved = 7;
const int NetlinkEvent::NlActionRdnss = 8;
NetlinkEvent::NetlinkEvent() {
mAction = NlActionUnknown;
@ -76,7 +78,7 @@ void NetlinkEvent::dump() {
}
/*
* Decode a RTM_NEWADDR or RTM_DELADDR message.
* Parse a RTM_NEWADDR or RTM_DELADDR message.
*/
bool NetlinkEvent::parseIfAddrMessage(int type, struct ifaddrmsg *ifaddr,
int rtasize) {
@ -172,13 +174,111 @@ bool NetlinkEvent::parseIfAddrMessage(int type, struct ifaddrmsg *ifaddr,
}
/*
* Parse an binary message from a NETLINK_ROUTE netlink socket.
* Parse a RTM_NEWNDUSEROPT message.
*/
bool NetlinkEvent::parseNdUserOptMessage(struct nduseroptmsg *msg, int len) {
// Check the length is valid.
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 + 1];
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;
}
int numaddrs = (optlen - 1) / 2;
// Find the lifetime.
struct nd_opt_rdnss *rndss_opt = (struct nd_opt_rdnss *) opthdr;
uint32_t lifetime = ntohl(rndss_opt->nd_opt_rdnss_lifetime);
// Construct "SERVERS=<comma-separated string of DNS addresses>".
// Reserve (INET6_ADDRSTRLEN + 1) chars for each address: all but the
// the last address are followed by ','; the last is followed by '\0'.
static const char kServerTag[] = "SERVERS=";
static const int kTagLength = sizeof(kServerTag) - 1;
int bufsize = kTagLength + numaddrs * (INET6_ADDRSTRLEN + 1);
char *buf = (char *) malloc(bufsize);
if (!buf) {
SLOGE("RDNSS option: out of memory\n");
return false;
}
strcpy(buf, kServerTag);
int 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);
}
buf[pos] = '\0';
mAction = NlActionRdnss;
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.
*/
bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) {
const struct nlmsghdr *nh;
for (nh = (struct nlmsghdr *) buffer;
NLMSG_OK(nh, size) && (nh->nlmsg_type != NLMSG_DONE);
NLMSG_OK(nh, (unsigned) size) && (nh->nlmsg_type != NLMSG_DONE);
nh = NLMSG_NEXT(nh, size)) {
if (nh->nlmsg_type == RTM_NEWLINK) {
@ -245,8 +345,25 @@ bool NetlinkEvent::parseBinaryNetlinkMessage(char *buffer, int size) {
if (!parseIfAddrMessage(nh->nlmsg_type, ifa, rtasize)) {
continue;
}
} else if (nh->nlmsg_type == RTM_NEWNDUSEROPT) {
int len = nh->nlmsg_len - sizeof(*nh);
struct nduseroptmsg *ndmsg = (struct nduseroptmsg *) NLMSG_DATA(nh);
if (sizeof(*ndmsg) > (size_t) len) {
SLOGE("Got a short RTM_NEWNDUSEROPT message\n");
continue;
}
size_t optsize = NLMSG_PAYLOAD(nh, sizeof(*ndmsg));
if (!parseNdUserOptMessage(ndmsg, optsize)) {
continue;
}
} else {
SLOGD("Unexpected netlink message. type=0x%x\n", nh->nlmsg_type);
SLOGD("Unexpected netlink message. type=0x%x\n",
nh->nlmsg_type);
}
}