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-rw-r--r--fs/afs/use-rtnetlink.c473
1 files changed, 473 insertions, 0 deletions
diff --git a/fs/afs/use-rtnetlink.c b/fs/afs/use-rtnetlink.c
new file mode 100644
index 00000000000..82f0daa2897
--- /dev/null
+++ b/fs/afs/use-rtnetlink.c
@@ -0,0 +1,473 @@
+/* RTNETLINK client
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <linux/netlink.h>
+#include <linux/rtnetlink.h>
+#include <linux/if_addr.h>
+#include <linux/if_arp.h>
+#include <linux/inetdevice.h>
+#include <net/netlink.h>
+#include "internal.h"
+
+struct afs_rtm_desc {
+ struct socket *nlsock;
+ struct afs_interface *bufs;
+ u8 *mac;
+ size_t nbufs;
+ size_t maxbufs;
+ void *data;
+ ssize_t datalen;
+ size_t datamax;
+ int msg_seq;
+ unsigned mac_index;
+ bool wantloopback;
+ int (*parse)(struct afs_rtm_desc *, struct nlmsghdr *);
+};
+
+/*
+ * parse an RTM_GETADDR response
+ */
+static int afs_rtm_getaddr_parse(struct afs_rtm_desc *desc,
+ struct nlmsghdr *nlhdr)
+{
+ struct afs_interface *this;
+ struct ifaddrmsg *ifa;
+ struct rtattr *rtattr;
+ const char *name;
+ size_t len;
+
+ ifa = (struct ifaddrmsg *) NLMSG_DATA(nlhdr);
+
+ _enter("{ix=%d,af=%d}", ifa->ifa_index, ifa->ifa_family);
+
+ if (ifa->ifa_family != AF_INET) {
+ _leave(" = 0 [family %d]", ifa->ifa_family);
+ return 0;
+ }
+ if (desc->nbufs >= desc->maxbufs) {
+ _leave(" = 0 [max %zu/%zu]", desc->nbufs, desc->maxbufs);
+ return 0;
+ }
+
+ this = &desc->bufs[desc->nbufs];
+
+ this->index = ifa->ifa_index;
+ this->netmask.s_addr = inet_make_mask(ifa->ifa_prefixlen);
+ this->mtu = 0;
+
+ rtattr = NLMSG_DATA(nlhdr) + NLMSG_ALIGN(sizeof(struct ifaddrmsg));
+ len = NLMSG_PAYLOAD(nlhdr, sizeof(struct ifaddrmsg));
+
+ name = "unknown";
+ for (; RTA_OK(rtattr, len); rtattr = RTA_NEXT(rtattr, len)) {
+ switch (rtattr->rta_type) {
+ case IFA_ADDRESS:
+ memcpy(&this->address, RTA_DATA(rtattr), 4);
+ break;
+ case IFA_LABEL:
+ name = RTA_DATA(rtattr);
+ break;
+ }
+ }
+
+ _debug("%s: "NIPQUAD_FMT"/"NIPQUAD_FMT,
+ name, NIPQUAD(this->address), NIPQUAD(this->netmask));
+
+ desc->nbufs++;
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * parse an RTM_GETLINK response for MTUs
+ */
+static int afs_rtm_getlink_if_parse(struct afs_rtm_desc *desc,
+ struct nlmsghdr *nlhdr)
+{
+ struct afs_interface *this;
+ struct ifinfomsg *ifi;
+ struct rtattr *rtattr;
+ const char *name;
+ size_t len, loop;
+
+ ifi = (struct ifinfomsg *) NLMSG_DATA(nlhdr);
+
+ _enter("{ix=%d}", ifi->ifi_index);
+
+ for (loop = 0; loop < desc->nbufs; loop++) {
+ this = &desc->bufs[loop];
+ if (this->index == ifi->ifi_index)
+ goto found;
+ }
+
+ _leave(" = 0 [no match]");
+ return 0;
+
+found:
+ if (ifi->ifi_type == ARPHRD_LOOPBACK && !desc->wantloopback) {
+ _leave(" = 0 [loopback]");
+ return 0;
+ }
+
+ rtattr = NLMSG_DATA(nlhdr) + NLMSG_ALIGN(sizeof(struct ifinfomsg));
+ len = NLMSG_PAYLOAD(nlhdr, sizeof(struct ifinfomsg));
+
+ name = "unknown";
+ for (; RTA_OK(rtattr, len); rtattr = RTA_NEXT(rtattr, len)) {
+ switch (rtattr->rta_type) {
+ case IFLA_MTU:
+ memcpy(&this->mtu, RTA_DATA(rtattr), 4);
+ break;
+ case IFLA_IFNAME:
+ name = RTA_DATA(rtattr);
+ break;
+ }
+ }
+
+ _debug("%s: "NIPQUAD_FMT"/"NIPQUAD_FMT" mtu %u",
+ name, NIPQUAD(this->address), NIPQUAD(this->netmask),
+ this->mtu);
+
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * parse an RTM_GETLINK response for the MAC address belonging to the lowest
+ * non-internal interface
+ */
+static int afs_rtm_getlink_mac_parse(struct afs_rtm_desc *desc,
+ struct nlmsghdr *nlhdr)
+{
+ struct ifinfomsg *ifi;
+ struct rtattr *rtattr;
+ const char *name;
+ size_t remain, len;
+ bool set;
+
+ ifi = (struct ifinfomsg *) NLMSG_DATA(nlhdr);
+
+ _enter("{ix=%d}", ifi->ifi_index);
+
+ if (ifi->ifi_index >= desc->mac_index) {
+ _leave(" = 0 [high]");
+ return 0;
+ }
+ if (ifi->ifi_type == ARPHRD_LOOPBACK) {
+ _leave(" = 0 [loopback]");
+ return 0;
+ }
+
+ rtattr = NLMSG_DATA(nlhdr) + NLMSG_ALIGN(sizeof(struct ifinfomsg));
+ remain = NLMSG_PAYLOAD(nlhdr, sizeof(struct ifinfomsg));
+
+ name = "unknown";
+ set = false;
+ for (; RTA_OK(rtattr, remain); rtattr = RTA_NEXT(rtattr, remain)) {
+ switch (rtattr->rta_type) {
+ case IFLA_ADDRESS:
+ len = RTA_PAYLOAD(rtattr);
+ memcpy(desc->mac, RTA_DATA(rtattr),
+ min_t(size_t, len, 6));
+ desc->mac_index = ifi->ifi_index;
+ set = true;
+ break;
+ case IFLA_IFNAME:
+ name = RTA_DATA(rtattr);
+ break;
+ }
+ }
+
+ if (set)
+ _debug("%s: %02x:%02x:%02x:%02x:%02x:%02x",
+ name,
+ desc->mac[0], desc->mac[1], desc->mac[2],
+ desc->mac[3], desc->mac[4], desc->mac[5]);
+
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * read the rtnetlink response and pass to parsing routine
+ */
+static int afs_read_rtm(struct afs_rtm_desc *desc)
+{
+ struct nlmsghdr *nlhdr, tmphdr;
+ struct msghdr msg;
+ struct kvec iov[1];
+ void *data;
+ bool last = false;
+ int len, ret, remain;
+
+ _enter("");
+
+ do {
+ /* first of all peek to see how big the packet is */
+ memset(&msg, 0, sizeof(msg));
+ iov[0].iov_base = &tmphdr;
+ iov[0].iov_len = sizeof(tmphdr);
+ len = kernel_recvmsg(desc->nlsock, &msg, iov, 1,
+ sizeof(tmphdr), MSG_PEEK | MSG_TRUNC);
+ if (len < 0) {
+ _leave(" = %d [peek]", len);
+ return len;
+ }
+ if (len == 0)
+ continue;
+ if (len < sizeof(tmphdr) || len < NLMSG_PAYLOAD(&tmphdr, 0)) {
+ _leave(" = -EMSGSIZE");
+ return -EMSGSIZE;
+ }
+
+ if (desc->datamax < len) {
+ kfree(desc->data);
+ desc->data = NULL;
+ data = kmalloc(len, GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+ desc->data = data;
+ }
+ desc->datamax = len;
+
+ /* read all the data from this packet */
+ iov[0].iov_base = desc->data;
+ iov[0].iov_len = desc->datamax;
+ desc->datalen = kernel_recvmsg(desc->nlsock, &msg, iov, 1,
+ desc->datamax, 0);
+ if (desc->datalen < 0) {
+ _leave(" = %ld [recv]", desc->datalen);
+ return desc->datalen;
+ }
+
+ nlhdr = desc->data;
+
+ /* check if the header is valid */
+ if (!NLMSG_OK(nlhdr, desc->datalen) ||
+ nlhdr->nlmsg_type == NLMSG_ERROR) {
+ _leave(" = -EIO");
+ return -EIO;
+ }
+
+ /* see if this is the last message */
+ if (nlhdr->nlmsg_type == NLMSG_DONE ||
+ !(nlhdr->nlmsg_flags & NLM_F_MULTI))
+ last = true;
+
+ /* parse the bits we got this time */
+ nlmsg_for_each_msg(nlhdr, desc->data, desc->datalen, remain) {
+ ret = desc->parse(desc, nlhdr);
+ if (ret < 0) {
+ _leave(" = %d [parse]", ret);
+ return ret;
+ }
+ }
+
+ } while (!last);
+
+ _leave(" = 0");
+ return 0;
+}
+
+/*
+ * list the interface bound addresses to get the address and netmask
+ */
+static int afs_rtm_getaddr(struct afs_rtm_desc *desc)
+{
+ struct msghdr msg;
+ struct kvec iov[1];
+ int ret;
+
+ struct {
+ struct nlmsghdr nl_msg __attribute__((aligned(NLMSG_ALIGNTO)));
+ struct ifaddrmsg addr_msg __attribute__((aligned(NLMSG_ALIGNTO)));
+ } request;
+
+ _enter("");
+
+ memset(&request, 0, sizeof(request));
+
+ request.nl_msg.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
+ request.nl_msg.nlmsg_type = RTM_GETADDR;
+ request.nl_msg.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
+ request.nl_msg.nlmsg_seq = desc->msg_seq++;
+ request.nl_msg.nlmsg_pid = 0;
+
+ memset(&msg, 0, sizeof(msg));
+ iov[0].iov_base = &request;
+ iov[0].iov_len = sizeof(request);
+
+ ret = kernel_sendmsg(desc->nlsock, &msg, iov, 1, iov[0].iov_len);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * list the interface link statuses to get the MTUs
+ */
+static int afs_rtm_getlink(struct afs_rtm_desc *desc)
+{
+ struct msghdr msg;
+ struct kvec iov[1];
+ int ret;
+
+ struct {
+ struct nlmsghdr nl_msg __attribute__((aligned(NLMSG_ALIGNTO)));
+ struct ifinfomsg link_msg __attribute__((aligned(NLMSG_ALIGNTO)));
+ } request;
+
+ _enter("");
+
+ memset(&request, 0, sizeof(request));
+
+ request.nl_msg.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
+ request.nl_msg.nlmsg_type = RTM_GETLINK;
+ request.nl_msg.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
+ request.nl_msg.nlmsg_seq = desc->msg_seq++;
+ request.nl_msg.nlmsg_pid = 0;
+
+ memset(&msg, 0, sizeof(msg));
+ iov[0].iov_base = &request;
+ iov[0].iov_len = sizeof(request);
+
+ ret = kernel_sendmsg(desc->nlsock, &msg, iov, 1, iov[0].iov_len);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * cull any interface records for which there isn't an MTU value
+ */
+static void afs_cull_interfaces(struct afs_rtm_desc *desc)
+{
+ struct afs_interface *bufs = desc->bufs;
+ size_t nbufs = desc->nbufs;
+ int loop, point = 0;
+
+ _enter("{%zu}", nbufs);
+
+ for (loop = 0; loop < nbufs; loop++) {
+ if (desc->bufs[loop].mtu != 0) {
+ if (loop != point) {
+ ASSERTCMP(loop, >, point);
+ bufs[point] = bufs[loop];
+ }
+ point++;
+ }
+ }
+
+ desc->nbufs = point;
+ _leave(" [%zu/%zu]", desc->nbufs, nbufs);
+}
+
+/*
+ * get a list of this system's interface IPv4 addresses, netmasks and MTUs
+ * - returns the number of interface records in the buffer
+ */
+int afs_get_ipv4_interfaces(struct afs_interface *bufs, size_t maxbufs,
+ bool wantloopback)
+{
+ struct afs_rtm_desc desc;
+ int ret, loop;
+
+ _enter("");
+
+ memset(&desc, 0, sizeof(desc));
+ desc.bufs = bufs;
+ desc.maxbufs = maxbufs;
+ desc.wantloopback = wantloopback;
+
+ ret = sock_create_kern(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE,
+ &desc.nlsock);
+ if (ret < 0) {
+ _leave(" = %d [sock]", ret);
+ return ret;
+ }
+
+ /* issue RTM_GETADDR */
+ desc.parse = afs_rtm_getaddr_parse;
+ ret = afs_rtm_getaddr(&desc);
+ if (ret < 0)
+ goto error;
+ ret = afs_read_rtm(&desc);
+ if (ret < 0)
+ goto error;
+
+ /* issue RTM_GETLINK */
+ desc.parse = afs_rtm_getlink_if_parse;
+ ret = afs_rtm_getlink(&desc);
+ if (ret < 0)
+ goto error;
+ ret = afs_read_rtm(&desc);
+ if (ret < 0)
+ goto error;
+
+ afs_cull_interfaces(&desc);
+ ret = desc.nbufs;
+
+ for (loop = 0; loop < ret; loop++)
+ _debug("[%d] "NIPQUAD_FMT"/"NIPQUAD_FMT" mtu %u",
+ bufs[loop].index,
+ NIPQUAD(bufs[loop].address),
+ NIPQUAD(bufs[loop].netmask),
+ bufs[loop].mtu);
+
+error:
+ kfree(desc.data);
+ sock_release(desc.nlsock);
+ _leave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * get a MAC address from a random ethernet interface that has a real one
+ * - the buffer should be 6 bytes in size
+ */
+int afs_get_MAC_address(u8 mac[6])
+{
+ struct afs_rtm_desc desc;
+ int ret;
+
+ _enter("");
+
+ memset(&desc, 0, sizeof(desc));
+ desc.mac = mac;
+ desc.mac_index = UINT_MAX;
+
+ ret = sock_create_kern(AF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE,
+ &desc.nlsock);
+ if (ret < 0) {
+ _leave(" = %d [sock]", ret);
+ return ret;
+ }
+
+ /* issue RTM_GETLINK */
+ desc.parse = afs_rtm_getlink_mac_parse;
+ ret = afs_rtm_getlink(&desc);
+ if (ret < 0)
+ goto error;
+ ret = afs_read_rtm(&desc);
+ if (ret < 0)
+ goto error;
+
+ if (desc.mac_index < UINT_MAX) {
+ /* got a MAC address */
+ _debug("[%d] %02x:%02x:%02x:%02x:%02x:%02x",
+ desc.mac_index,
+ mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
+ } else {
+ ret = -ENONET;
+ }
+
+error:
+ sock_release(desc.nlsock);
+ _leave(" = %d", ret);
+ return ret;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-15 15:05:07 +0000