From 47ddb515b7d59b29d83628c1b4e48642dc0e49ba Mon Sep 17 00:00:00 2001 From: Lorenzo Colitti Date: Mon, 26 Sep 2011 10:49:41 -0700 Subject: Support adding, deleting, and clearing IPv6 addrs. - Provide a function to add and delete IPv4/IPv6 addresses using netlink. - Provide a function that clears all IP addresses on an interface that can be used by netd. Also, a couple of cleanups: - Update the header file to match reality, and include the header file in the implementation. Also fix a caller that has an incorrect method signature. - Fix whitespace in Android.mk. Change-Id: Ifba9d60cdfffb0b7e5c3b9c6ab328f5f77d259c4 --- libnetutils/Android.mk | 4 +- libnetutils/ifc_utils.c | 212 +++++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 211 insertions(+), 5 deletions(-) (limited to 'libnetutils') diff --git a/libnetutils/Android.mk b/libnetutils/Android.mk index 1ef7da9..5f5849f 100644 --- a/libnetutils/Android.mk +++ b/libnetutils/Android.mk @@ -6,10 +6,10 @@ LOCAL_SRC_FILES:= \ dhcpmsg.c \ dhcp_utils.c \ ifc_utils.c \ - packet.c + packet.c LOCAL_SHARED_LIBRARIES := \ - libcutils + libcutils LOCAL_MODULE:= libnetutils diff --git a/libnetutils/ifc_utils.c b/libnetutils/ifc_utils.c index c482736..0a2f760 100644 --- a/libnetutils/ifc_utils.c +++ b/libnetutils/ifc_utils.c @@ -26,15 +26,18 @@ #include #include #include +#include #include #include #include -#include +#include #include #include -#include -#include +#include +#include + +#include "netutils/ifc.h" #ifdef ANDROID #define LOG_TAG "NetUtils" @@ -52,6 +55,8 @@ static int ifc_ctl_sock6 = -1; void printerr(char *fmt, ...); #define DBG 0 +#define INET_ADDRLEN 4 +#define INET6_ADDRLEN 16 in_addr_t prefixLengthToIpv4Netmask(int prefix_length) { @@ -88,6 +93,28 @@ static const char *ipaddr_to_string(in_addr_t addr) return inet_ntoa(in_addr); } +int string_to_ip(const char *string, struct sockaddr_storage *ss) { + struct addrinfo hints, *ai; + int ret; + + if (ss == NULL) { + return -EFAULT; + } + + memset(&hints, 0, sizeof(hints)); + hints.ai_family = AF_UNSPEC; + hints.ai_flags = AI_NUMERICHOST; + hints.ai_socktype = SOCK_DGRAM; + + ret = getaddrinfo(string, NULL, &hints, &ai); + if (ret == 0) { + memcpy(ss, ai->ai_addr, ai->ai_addrlen); + freeaddrinfo(ai); + } + + return ret; +} + int ifc_init(void) { int ret; @@ -209,6 +236,185 @@ int ifc_set_addr(const char *name, in_addr_t addr) return ret; } +/* + * Adds or deletes an IP address on an interface. + * + * Action is one of: + * - RTM_NEWADDR (to add a new address) + * - RTM_DELADDR (to delete an existing address) + * + * Returns zero on success and negative errno on failure. + */ +int ifc_act_on_address(int action, const char *name, const char *address, + int prefixlen) { + int ifindex, s, len, ret; + struct sockaddr_storage ss; + void *addr; + size_t addrlen; + struct { + struct nlmsghdr n; + struct ifaddrmsg r; + // Allow for IPv6 address, headers, and padding. + char attrbuf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) + + NLMSG_ALIGN(sizeof(struct rtattr)) + + NLMSG_ALIGN(INET6_ADDRLEN)]; + } req; + struct rtattr *rta; + struct nlmsghdr *nh; + struct nlmsgerr *err; + char buf[NLMSG_ALIGN(sizeof(struct nlmsghdr)) + + NLMSG_ALIGN(sizeof(struct nlmsgerr)) + + NLMSG_ALIGN(sizeof(struct nlmsghdr))]; + + // Get interface ID. + ifindex = if_nametoindex(name); + if (ifindex == 0) { + return -errno; + } + + // Convert string representation to sockaddr_storage. + ret = string_to_ip(address, &ss); + if (ret) { + return ret; + } + + // Determine address type and length. + if (ss.ss_family == AF_INET) { + struct sockaddr_in *sin = (struct sockaddr_in *) &ss; + addr = &sin->sin_addr; + addrlen = INET_ADDRLEN; + } else if (ss.ss_family == AF_INET6) { + struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &ss; + addr = &sin6->sin6_addr; + addrlen = INET6_ADDRLEN; + } else { + return -EAFNOSUPPORT; + } + + // Fill in netlink structures. + memset(&req, 0, sizeof(req)); + + // Netlink message header. + req.n.nlmsg_len = NLMSG_LENGTH(sizeof(req.r)); + req.n.nlmsg_type = action; + req.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK; + req.n.nlmsg_pid = getpid(); + + // Interface address message header. + req.r.ifa_family = ss.ss_family; + req.r.ifa_prefixlen = prefixlen; + req.r.ifa_index = ifindex; + + // Routing attribute. Contains the actual IP address. + rta = (struct rtattr *) (((char *) &req) + NLMSG_ALIGN(req.n.nlmsg_len)); + rta->rta_type = IFA_LOCAL; + rta->rta_len = RTA_LENGTH(addrlen); + req.n.nlmsg_len = NLMSG_ALIGN(req.n.nlmsg_len) + RTA_LENGTH(addrlen); + memcpy(RTA_DATA(rta), addr, addrlen); + + s = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE); + if (send(s, &req, req.n.nlmsg_len, 0) < 0) { + close(s); + return -errno; + } + + len = recv(s, buf, sizeof(buf), 0); + close(s); + if (len < 0) { + return -errno; + } + + // Parse the acknowledgement to find the return code. + nh = (struct nlmsghdr *) buf; + if (!NLMSG_OK(nh, (unsigned) len) || nh->nlmsg_type != NLMSG_ERROR) { + return -EINVAL; + } + err = NLMSG_DATA(nh); + + // Return code is negative errno. + return err->error; +} + +int ifc_add_address(const char *name, const char *address, int prefixlen) { + return ifc_act_on_address(RTM_NEWADDR, name, address, prefixlen); +} + +int ifc_del_address(const char *name, const char * address, int prefixlen) { + return ifc_act_on_address(RTM_DELADDR, name, address, prefixlen); +} + +/* + * Clears IPv6 addresses on the specified interface. + */ +int ifc_clear_ipv6_addresses(const char *name) { + char rawaddrstr[INET6_ADDRSTRLEN], addrstr[INET6_ADDRSTRLEN]; + unsigned int prefixlen; + int lasterror = 0, i, j, ret; + char ifname[64]; // Currently, IFNAMSIZ = 16. + FILE *f = fopen("/proc/net/if_inet6", "r"); + if (!f) { + return -errno; + } + + // Format: + // 20010db8000a0001fc446aa4b5b347ed 03 40 00 01 wlan0 + while (fscanf(f, "%32s %*02x %02x %*02x %*02x %63s\n", + rawaddrstr, &prefixlen, ifname) == 3) { + // Is this the interface we're looking for? + if (strcmp(name, ifname)) { + continue; + } + + // Put the colons back into the address. + for (i = 0, j = 0; i < 32; i++, j++) { + addrstr[j] = rawaddrstr[i]; + if (i % 4 == 3) { + addrstr[++j] = ':'; + } + } + addrstr[j - 1] = '\0'; + + // Don't delete the link-local address as well, or it will disable IPv6 + // on the interface. + if (strncmp(addrstr, "fe80:", 5) == 0) { + continue; + } + + ret = ifc_del_address(ifname, addrstr, prefixlen); + if (ret) { + LOGE("Deleting address %s/%d on %s: %s", addrstr, prefixlen, ifname, + strerror(-ret)); + lasterror = ret; + } + } + + fclose(f); + return lasterror; +} + +/* + * Clears IPv4 addresses on the specified interface. + */ +void ifc_clear_ipv4_addresses(const char *name) { + unsigned count, addr; + ifc_init(); + for (count=0, addr=1;((addr != 0) && (count < 255)); count++) { + if (ifc_get_addr(name, &addr) < 0) + break; + if (addr) + ifc_set_addr(name, 0); + } + ifc_close(); +} + +/* + * Clears all IP addresses on the specified interface. + */ +int ifc_clear_addresses(const char *name) { + ifc_clear_ipv4_addresses(name); + return ifc_clear_ipv6_addresses(name); +} + int ifc_set_hwaddr(const char *name, const void *ptr) { int r; -- cgit v1.1