1 /* 2 * Copyright (c) 2012 GCT Semiconductor, Inc. All rights reserved. 3 * 4 * This software is licensed under the terms of the GNU General Public 5 * License version 2, as published by the Free Software Foundation, and 6 * may be copied, distributed, and modified under those terms. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 */ 13 14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 15 16 #include <linux/export.h> 17 #include <linux/mutex.h> 18 #include <linux/etherdevice.h> 19 #include <linux/netlink.h> 20 #include <asm/byteorder.h> 21 #include <net/sock.h> 22 23 #include "netlink_k.h" 24 25 static DEFINE_MUTEX(netlink_mutex); 26 27 #define ND_MAX_GROUP 30 28 #define ND_IFINDEX_LEN sizeof(int) 29 #define ND_NLMSG_SPACE(len) (NLMSG_SPACE(len) + ND_IFINDEX_LEN) 30 #define ND_NLMSG_DATA(nlh) ((void *)((char *)NLMSG_DATA(nlh) + \ 31 ND_IFINDEX_LEN)) 32 #define ND_NLMSG_S_LEN(len) (len + ND_IFINDEX_LEN) 33 #define ND_NLMSG_R_LEN(nlh) (nlh->nlmsg_len - ND_IFINDEX_LEN) 34 #define ND_NLMSG_IFIDX(nlh) NLMSG_DATA(nlh) 35 #define ND_MAX_MSG_LEN (1024 * 32) 36 37 static void (*rcv_cb)(struct net_device *dev, u16 type, void *msg, int len); 38 39 static void netlink_rcv_cb(struct sk_buff *skb) 40 { 41 struct nlmsghdr *nlh; 42 struct net_device *dev; 43 u32 mlen; 44 void *msg; 45 int ifindex; 46 47 if (!rcv_cb) { 48 pr_err("nl cb - unregistered\n"); 49 return; 50 } 51 52 if (skb->len < NLMSG_HDRLEN) { 53 pr_err("nl cb - invalid skb length\n"); 54 return; 55 } 56 57 nlh = (struct nlmsghdr *)skb->data; 58 59 if (skb->len < nlh->nlmsg_len || nlh->nlmsg_len > ND_MAX_MSG_LEN) { 60 pr_err("nl cb - invalid length (%d,%d)\n", 61 skb->len, nlh->nlmsg_len); 62 return; 63 } 64 65 memcpy(&ifindex, ND_NLMSG_IFIDX(nlh), ND_IFINDEX_LEN); 66 msg = ND_NLMSG_DATA(nlh); 67 mlen = ND_NLMSG_R_LEN(nlh); 68 69 dev = dev_get_by_index(&init_net, ifindex); 70 if (dev) { 71 rcv_cb(dev, nlh->nlmsg_type, msg, mlen); 72 dev_put(dev); 73 } else { 74 pr_err("nl cb - dev (%d) not found\n", ifindex); 75 } 76 } 77 78 static void netlink_rcv(struct sk_buff *skb) 79 { 80 mutex_lock(&netlink_mutex); 81 netlink_rcv_cb(skb); 82 mutex_unlock(&netlink_mutex); 83 } 84 85 struct sock *netlink_init(int unit, 86 void (*cb)(struct net_device *dev, u16 type, 87 void *msg, int len)) 88 { 89 struct sock *sock; 90 struct netlink_kernel_cfg cfg = { 91 .input = netlink_rcv, 92 }; 93 94 sock = netlink_kernel_create(&init_net, unit, &cfg); 95 96 if (sock) 97 rcv_cb = cb; 98 99 return sock; 100 } 101 102 int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len) 103 { 104 static u32 seq; 105 struct sk_buff *skb = NULL; 106 struct nlmsghdr *nlh; 107 int ret = 0; 108 109 if (group > ND_MAX_GROUP) 110 return -EINVAL; 111 112 if (!netlink_has_listeners(sock, group + 1)) 113 return -ESRCH; 114 115 skb = alloc_skb(NLMSG_SPACE(len), GFP_ATOMIC); 116 if (!skb) 117 return -ENOMEM; 118 119 seq++; 120 121 nlh = nlmsg_put(skb, 0, seq, type, len, 0); 122 memcpy(NLMSG_DATA(nlh), msg, len); 123 NETLINK_CB(skb).portid = 0; 124 NETLINK_CB(skb).dst_group = 0; 125 126 ret = netlink_broadcast(sock, skb, 0, group + 1, GFP_ATOMIC); 127 if (!ret) 128 return len; 129 130 if (ret != -ESRCH) 131 pr_err("nl broadcast g=%d, t=%d, l=%d, r=%d\n", 132 group, type, len, ret); 133 else if (netlink_has_listeners(sock, group + 1)) 134 return -EAGAIN; 135 136 return ret; 137 } 138