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) + ND_IFINDEX_LEN)) 36 #define ND_NLMSG_S_LEN(len) (len+ND_IFINDEX_LEN) 37 #define ND_NLMSG_R_LEN(nlh) (nlh->nlmsg_len-ND_IFINDEX_LEN) 38 #define ND_NLMSG_IFIDX(nlh) NLMSG_DATA(nlh) 39 #define ND_MAX_MSG_LEN (1024 * 32) 40 41 static void (*rcv_cb)(struct net_device *dev, u16 type, void *msg, int len); 42 43 static void netlink_rcv_cb(struct sk_buff *skb) 44 { 45 struct nlmsghdr *nlh; 46 struct net_device *dev; 47 u32 mlen; 48 void *msg; 49 int ifindex; 50 51 if (!rcv_cb) { 52 pr_err("nl cb - unregistered\n"); 53 return; 54 } 55 56 if (skb->len < NLMSG_SPACE(0)) { 57 pr_err("nl cb - invalid skb length\n"); 58 return; 59 } 60 61 nlh = (struct nlmsghdr *)skb->data; 62 63 if (skb->len < nlh->nlmsg_len || nlh->nlmsg_len > ND_MAX_MSG_LEN) { 64 pr_err("nl cb - invalid length (%d,%d)\n", 65 skb->len, nlh->nlmsg_len); 66 return; 67 } 68 69 memcpy(&ifindex, ND_NLMSG_IFIDX(nlh), ND_IFINDEX_LEN); 70 msg = ND_NLMSG_DATA(nlh); 71 mlen = ND_NLMSG_R_LEN(nlh); 72 73 dev = dev_get_by_index(&init_net, ifindex); 74 if (dev) { 75 rcv_cb(dev, nlh->nlmsg_type, msg, mlen); 76 dev_put(dev); 77 } else { 78 pr_err("nl cb - dev (%d) not found\n", ifindex); 79 } 80 } 81 82 static void netlink_rcv(struct sk_buff *skb) 83 { 84 mutex_lock(&netlink_mutex); 85 netlink_rcv_cb(skb); 86 mutex_unlock(&netlink_mutex); 87 } 88 89 struct sock *netlink_init(int unit, 90 void (*cb)(struct net_device *dev, u16 type, void *msg, int len)) 91 { 92 struct sock *sock; 93 struct netlink_kernel_cfg cfg = { 94 .input = netlink_rcv, 95 }; 96 97 #if !defined(DEFINE_MUTEX) 98 init_MUTEX(&netlink_mutex); 99 #endif 100 101 sock = netlink_kernel_create(&init_net, unit, &cfg); 102 103 if (sock) 104 rcv_cb = cb; 105 106 return sock; 107 } 108 109 void netlink_exit(struct sock *sock) 110 { 111 sock_release(sock->sk_socket); 112 } 113 114 int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len) 115 { 116 static u32 seq; 117 struct sk_buff *skb = NULL; 118 struct nlmsghdr *nlh; 119 int ret = 0; 120 121 if (group > ND_MAX_GROUP) 122 return -EINVAL; 123 124 if (!netlink_has_listeners(sock, group+1)) 125 return -ESRCH; 126 127 skb = alloc_skb(NLMSG_SPACE(len), GFP_ATOMIC); 128 if (!skb) 129 return -ENOMEM; 130 131 seq++; 132 133 nlh = nlmsg_put(skb, 0, seq, type, len, 0); 134 memcpy(NLMSG_DATA(nlh), msg, len); 135 NETLINK_CB(skb).portid = 0; 136 NETLINK_CB(skb).dst_group = 0; 137 138 ret = netlink_broadcast(sock, skb, 0, group+1, GFP_ATOMIC); 139 if (!ret) 140 return len; 141 142 if (ret != -ESRCH) 143 pr_err("nl broadcast g=%d, t=%d, l=%d, r=%d\n", 144 group, type, len, ret); 145 else if (netlink_has_listeners(sock, group+1)) 146 return -EAGAIN; 147 148 return ret; 149 } 150