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/etherdevice.h> 18 #include <linux/netlink.h> 19 #include <asm/byteorder.h> 20 #include <net/sock.h> 21 22 #include "netlink_k.h" 23 24 #if defined(DEFINE_MUTEX) 25 static DEFINE_MUTEX(netlink_mutex); 26 #else 27 static struct semaphore netlink_mutex; 28 #define mutex_lock(x) down(x) 29 #define mutex_unlock(x) up(x) 30 #endif 31 32 #define ND_MAX_GROUP 30 33 #define ND_IFINDEX_LEN sizeof(int) 34 #define ND_NLMSG_SPACE(len) (NLMSG_SPACE(len) + ND_IFINDEX_LEN) 35 #define ND_NLMSG_DATA(nlh) ((void *)((char *)NLMSG_DATA(nlh) + \ 36 ND_IFINDEX_LEN)) 37 #define ND_NLMSG_S_LEN(len) (len + ND_IFINDEX_LEN) 38 #define ND_NLMSG_R_LEN(nlh) (nlh->nlmsg_len - ND_IFINDEX_LEN) 39 #define ND_NLMSG_IFIDX(nlh) NLMSG_DATA(nlh) 40 #define ND_MAX_MSG_LEN (1024 * 32) 41 42 static void (*rcv_cb)(struct net_device *dev, u16 type, void *msg, int len); 43 44 static void netlink_rcv_cb(struct sk_buff *skb) 45 { 46 struct nlmsghdr *nlh; 47 struct net_device *dev; 48 u32 mlen; 49 void *msg; 50 int ifindex; 51 52 if (!rcv_cb) { 53 pr_err("nl cb - unregistered\n"); 54 return; 55 } 56 57 if (skb->len < NLMSG_HDRLEN) { 58 pr_err("nl cb - invalid skb length\n"); 59 return; 60 } 61 62 nlh = (struct nlmsghdr *)skb->data; 63 64 if (skb->len < nlh->nlmsg_len || nlh->nlmsg_len > ND_MAX_MSG_LEN) { 65 pr_err("nl cb - invalid length (%d,%d)\n", 66 skb->len, nlh->nlmsg_len); 67 return; 68 } 69 70 memcpy(&ifindex, ND_NLMSG_IFIDX(nlh), ND_IFINDEX_LEN); 71 msg = ND_NLMSG_DATA(nlh); 72 mlen = ND_NLMSG_R_LEN(nlh); 73 74 dev = dev_get_by_index(&init_net, ifindex); 75 if (dev) { 76 rcv_cb(dev, nlh->nlmsg_type, msg, mlen); 77 dev_put(dev); 78 } else { 79 pr_err("nl cb - dev (%d) not found\n", ifindex); 80 } 81 } 82 83 static void netlink_rcv(struct sk_buff *skb) 84 { 85 mutex_lock(&netlink_mutex); 86 netlink_rcv_cb(skb); 87 mutex_unlock(&netlink_mutex); 88 } 89 90 struct sock *netlink_init(int unit, 91 void (*cb)(struct net_device *dev, u16 type, 92 void *msg, int len)) 93 { 94 struct sock *sock; 95 struct netlink_kernel_cfg cfg = { 96 .input = netlink_rcv, 97 }; 98 99 #if !defined(DEFINE_MUTEX) 100 init_MUTEX(&netlink_mutex); 101 #endif 102 103 sock = netlink_kernel_create(&init_net, unit, &cfg); 104 105 if (sock) 106 rcv_cb = cb; 107 108 return sock; 109 } 110 111 int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len) 112 { 113 static u32 seq; 114 struct sk_buff *skb = NULL; 115 struct nlmsghdr *nlh; 116 int ret = 0; 117 118 if (group > ND_MAX_GROUP) 119 return -EINVAL; 120 121 if (!netlink_has_listeners(sock, group + 1)) 122 return -ESRCH; 123 124 skb = alloc_skb(NLMSG_SPACE(len), GFP_ATOMIC); 125 if (!skb) 126 return -ENOMEM; 127 128 seq++; 129 130 nlh = nlmsg_put(skb, 0, seq, type, len, 0); 131 memcpy(NLMSG_DATA(nlh), msg, len); 132 NETLINK_CB(skb).portid = 0; 133 NETLINK_CB(skb).dst_group = 0; 134 135 ret = netlink_broadcast(sock, skb, 0, group + 1, GFP_ATOMIC); 136 if (!ret) 137 return len; 138 139 if (ret != -ESRCH) 140 pr_err("nl broadcast g=%d, t=%d, l=%d, r=%d\n", 141 group, type, len, ret); 142 else if (netlink_has_listeners(sock, group + 1)) 143 return -EAGAIN; 144 145 return ret; 146 } 147