1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2012 GCT Semiconductor, Inc. All rights reserved. */ 3 4 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 5 6 #include <linux/export.h> 7 #include <linux/mutex.h> 8 #include <linux/etherdevice.h> 9 #include <linux/netlink.h> 10 #include <asm/byteorder.h> 11 #include <net/sock.h> 12 13 #include "netlink_k.h" 14 15 static DEFINE_MUTEX(netlink_mutex); 16 17 #define ND_MAX_GROUP 30 18 #define ND_IFINDEX_LEN sizeof(int) 19 #define ND_NLMSG_SPACE(len) (NLMSG_SPACE(len) + ND_IFINDEX_LEN) 20 #define ND_NLMSG_DATA(nlh) ((void *)((char *)NLMSG_DATA(nlh) + \ 21 ND_IFINDEX_LEN)) 22 #define ND_NLMSG_S_LEN(len) (len + ND_IFINDEX_LEN) 23 #define ND_NLMSG_R_LEN(nlh) (nlh->nlmsg_len - ND_IFINDEX_LEN) 24 #define ND_NLMSG_IFIDX(nlh) NLMSG_DATA(nlh) 25 #define ND_MAX_MSG_LEN (1024 * 32) 26 27 static void (*rcv_cb)(struct net_device *dev, u16 type, void *msg, int len); 28 29 static void netlink_rcv_cb(struct sk_buff *skb) 30 { 31 struct nlmsghdr *nlh; 32 struct net_device *dev; 33 u32 mlen; 34 void *msg; 35 int ifindex; 36 37 if (!rcv_cb) { 38 pr_err("nl cb - unregistered\n"); 39 return; 40 } 41 42 if (skb->len < NLMSG_HDRLEN) { 43 pr_err("nl cb - invalid skb length\n"); 44 return; 45 } 46 47 nlh = (struct nlmsghdr *)skb->data; 48 49 if (skb->len < nlh->nlmsg_len || nlh->nlmsg_len > ND_MAX_MSG_LEN) { 50 pr_err("nl cb - invalid length (%d,%d)\n", 51 skb->len, nlh->nlmsg_len); 52 return; 53 } 54 55 memcpy(&ifindex, ND_NLMSG_IFIDX(nlh), ND_IFINDEX_LEN); 56 msg = ND_NLMSG_DATA(nlh); 57 mlen = ND_NLMSG_R_LEN(nlh); 58 59 dev = dev_get_by_index(&init_net, ifindex); 60 if (dev) { 61 rcv_cb(dev, nlh->nlmsg_type, msg, mlen); 62 dev_put(dev); 63 } else { 64 pr_err("nl cb - dev (%d) not found\n", ifindex); 65 } 66 } 67 68 static void netlink_rcv(struct sk_buff *skb) 69 { 70 mutex_lock(&netlink_mutex); 71 netlink_rcv_cb(skb); 72 mutex_unlock(&netlink_mutex); 73 } 74 75 struct sock *netlink_init(int unit, 76 void (*cb)(struct net_device *dev, u16 type, 77 void *msg, int len)) 78 { 79 struct sock *sock; 80 struct netlink_kernel_cfg cfg = { 81 .input = netlink_rcv, 82 }; 83 84 sock = netlink_kernel_create(&init_net, unit, &cfg); 85 86 if (sock) 87 rcv_cb = cb; 88 89 return sock; 90 } 91 92 int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len) 93 { 94 static u32 seq; 95 struct sk_buff *skb = NULL; 96 struct nlmsghdr *nlh; 97 int ret = 0; 98 99 if (group > ND_MAX_GROUP) 100 return -EINVAL; 101 102 if (!netlink_has_listeners(sock, group + 1)) 103 return -ESRCH; 104 105 skb = alloc_skb(NLMSG_SPACE(len), GFP_ATOMIC); 106 if (!skb) 107 return -ENOMEM; 108 109 seq++; 110 111 nlh = nlmsg_put(skb, 0, seq, type, len, 0); 112 memcpy(NLMSG_DATA(nlh), msg, len); 113 NETLINK_CB(skb).portid = 0; 114 NETLINK_CB(skb).dst_group = 0; 115 116 ret = netlink_broadcast(sock, skb, 0, group + 1, GFP_ATOMIC); 117 if (!ret) 118 return len; 119 120 if (ret != -ESRCH) 121 pr_err("nl broadcast g=%d, t=%d, l=%d, r=%d\n", 122 group, type, len, ret); 123 else if (netlink_has_listeners(sock, group + 1)) 124 return -EAGAIN; 125 126 return ret; 127 } 128