361 lines
11 KiB
C
361 lines
11 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_NETLINK_H
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#define __LINUX_NETLINK_H
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#include <linux/capability.h>
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#include <linux/skbuff.h>
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#include <linux/export.h>
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#include <net/scm.h>
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#include <uapi/linux/netlink.h>
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struct net;
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void do_trace_netlink_extack(const char *msg);
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static inline struct nlmsghdr *nlmsg_hdr(const struct sk_buff *skb)
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{
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return (struct nlmsghdr *)skb->data;
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}
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enum netlink_skb_flags {
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NETLINK_SKB_DST = 0x8, /* Dst set in sendto or sendmsg */
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};
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struct netlink_skb_parms {
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struct scm_creds creds; /* Skb credentials */
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__u32 portid;
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__u32 dst_group;
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__u32 flags;
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struct sock *sk;
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bool nsid_is_set;
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int nsid;
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};
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#define NETLINK_CB(skb) (*(struct netlink_skb_parms*)&((skb)->cb))
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#define NETLINK_CREDS(skb) (&NETLINK_CB((skb)).creds)
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void netlink_table_grab(void);
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void netlink_table_ungrab(void);
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#define NL_CFG_F_NONROOT_RECV (1 << 0)
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#define NL_CFG_F_NONROOT_SEND (1 << 1)
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/* optional Netlink kernel configuration parameters */
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struct netlink_kernel_cfg {
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unsigned int groups;
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unsigned int flags;
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void (*input)(struct sk_buff *skb);
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struct mutex *cb_mutex;
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int (*bind)(struct net *net, int group);
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void (*unbind)(struct net *net, int group);
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void (*release) (struct sock *sk, unsigned long *groups);
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};
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struct sock *__netlink_kernel_create(struct net *net, int unit,
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struct module *module,
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struct netlink_kernel_cfg *cfg);
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static inline struct sock *
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netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg)
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{
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return __netlink_kernel_create(net, unit, THIS_MODULE, cfg);
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}
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/* this can be increased when necessary - don't expose to userland */
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#define NETLINK_MAX_COOKIE_LEN 20
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#define NETLINK_MAX_FMTMSG_LEN 80
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/**
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* struct netlink_ext_ack - netlink extended ACK report struct
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* @_msg: message string to report - don't access directly, use
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* %NL_SET_ERR_MSG
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* @bad_attr: attribute with error
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* @policy: policy for a bad attribute
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* @miss_type: attribute type which was missing
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* @miss_nest: nest missing an attribute (%NULL if missing top level attr)
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* @cookie: cookie data to return to userspace (for success)
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* @cookie_len: actual cookie data length
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* @_msg_buf: output buffer for formatted message strings - don't access
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* directly, use %NL_SET_ERR_MSG_FMT
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*/
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struct netlink_ext_ack {
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const char *_msg;
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const struct nlattr *bad_attr;
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const struct nla_policy *policy;
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const struct nlattr *miss_nest;
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u16 miss_type;
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u8 cookie[NETLINK_MAX_COOKIE_LEN];
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u8 cookie_len;
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char _msg_buf[NETLINK_MAX_FMTMSG_LEN];
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};
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/* Always use this macro, this allows later putting the
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* message into a separate section or such for things
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* like translation or listing all possible messages.
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* If string formatting is needed use NL_SET_ERR_MSG_FMT.
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*/
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#define NL_SET_ERR_MSG(extack, msg) do { \
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static const char __msg[] = msg; \
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struct netlink_ext_ack *__extack = (extack); \
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\
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do_trace_netlink_extack(__msg); \
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\
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if (__extack) \
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__extack->_msg = __msg; \
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} while (0)
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/* We splice fmt with %s at each end even in the snprintf so that both calls
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* can use the same string constant, avoiding its duplication in .ro
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*/
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#define NL_SET_ERR_MSG_FMT(extack, fmt, args...) do { \
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struct netlink_ext_ack *__extack = (extack); \
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\
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if (!__extack) \
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break; \
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if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN, \
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"%s" fmt "%s", "", ##args, "") >= \
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NETLINK_MAX_FMTMSG_LEN) \
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net_warn_ratelimited("%s" fmt "%s", "truncated extack: ", \
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##args, "\n"); \
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\
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do_trace_netlink_extack(__extack->_msg_buf); \
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\
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__extack->_msg = __extack->_msg_buf; \
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} while (0)
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#define NL_SET_ERR_MSG_MOD(extack, msg) \
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NL_SET_ERR_MSG((extack), KBUILD_MODNAME ": " msg)
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#define NL_SET_ERR_MSG_FMT_MOD(extack, fmt, args...) \
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NL_SET_ERR_MSG_FMT((extack), KBUILD_MODNAME ": " fmt, ##args)
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#define NL_SET_ERR_MSG_WEAK(extack, msg) do { \
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if ((extack) && !(extack)->_msg) \
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NL_SET_ERR_MSG((extack), msg); \
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} while (0)
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#define NL_SET_ERR_MSG_WEAK_MOD(extack, msg) do { \
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if ((extack) && !(extack)->_msg) \
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NL_SET_ERR_MSG_MOD((extack), msg); \
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} while (0)
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#define NL_SET_BAD_ATTR_POLICY(extack, attr, pol) do { \
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if ((extack)) { \
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(extack)->bad_attr = (attr); \
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(extack)->policy = (pol); \
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} \
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} while (0)
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#define NL_SET_BAD_ATTR(extack, attr) NL_SET_BAD_ATTR_POLICY(extack, attr, NULL)
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#define NL_SET_ERR_MSG_ATTR_POL(extack, attr, pol, msg) do { \
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static const char __msg[] = msg; \
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struct netlink_ext_ack *__extack = (extack); \
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\
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do_trace_netlink_extack(__msg); \
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\
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if (__extack) { \
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__extack->_msg = __msg; \
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__extack->bad_attr = (attr); \
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__extack->policy = (pol); \
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} \
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} while (0)
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#define NL_SET_ERR_MSG_ATTR_POL_FMT(extack, attr, pol, fmt, args...) do { \
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struct netlink_ext_ack *__extack = (extack); \
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\
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if (!__extack) \
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break; \
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\
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if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN, \
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"%s" fmt "%s", "", ##args, "") >= \
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NETLINK_MAX_FMTMSG_LEN) \
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net_warn_ratelimited("%s" fmt "%s", "truncated extack: ", \
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##args, "\n"); \
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\
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do_trace_netlink_extack(__extack->_msg_buf); \
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\
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__extack->_msg = __extack->_msg_buf; \
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__extack->bad_attr = (attr); \
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__extack->policy = (pol); \
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} while (0)
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#define NL_SET_ERR_MSG_ATTR(extack, attr, msg) \
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NL_SET_ERR_MSG_ATTR_POL(extack, attr, NULL, msg)
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#define NL_SET_ERR_MSG_ATTR_FMT(extack, attr, msg, args...) \
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NL_SET_ERR_MSG_ATTR_POL_FMT(extack, attr, NULL, msg, ##args)
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#define NL_SET_ERR_ATTR_MISS(extack, nest, type) do { \
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struct netlink_ext_ack *__extack = (extack); \
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\
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if (__extack) { \
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__extack->miss_nest = (nest); \
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__extack->miss_type = (type); \
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} \
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} while (0)
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#define NL_REQ_ATTR_CHECK(extack, nest, tb, type) ({ \
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struct nlattr **__tb = (tb); \
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u32 __attr = (type); \
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int __retval; \
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\
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__retval = !__tb[__attr]; \
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if (__retval) \
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NL_SET_ERR_ATTR_MISS((extack), (nest), __attr); \
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__retval; \
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})
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static inline void nl_set_extack_cookie_u64(struct netlink_ext_ack *extack,
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u64 cookie)
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{
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if (!extack)
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return;
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memcpy(extack->cookie, &cookie, sizeof(cookie));
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extack->cookie_len = sizeof(cookie);
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}
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void netlink_kernel_release(struct sock *sk);
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int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
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int netlink_change_ngroups(struct sock *sk, unsigned int groups);
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void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
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void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
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const struct netlink_ext_ack *extack);
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int netlink_has_listeners(struct sock *sk, unsigned int group);
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bool netlink_strict_get_check(struct sk_buff *skb);
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int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
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int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
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__u32 group, gfp_t allocation);
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typedef int (*netlink_filter_fn)(struct sock *dsk, struct sk_buff *skb, void *data);
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int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
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__u32 portid, __u32 group, gfp_t allocation,
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netlink_filter_fn filter,
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void *filter_data);
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int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
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int netlink_register_notifier(struct notifier_block *nb);
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int netlink_unregister_notifier(struct notifier_block *nb);
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/* finegrained unicast helpers: */
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struct sock *netlink_getsockbyfilp(struct file *filp);
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int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
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long *timeo, struct sock *ssk);
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void netlink_detachskb(struct sock *sk, struct sk_buff *skb);
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int netlink_sendskb(struct sock *sk, struct sk_buff *skb);
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static inline struct sk_buff *
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netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
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{
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struct sk_buff *nskb;
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nskb = skb_clone(skb, gfp_mask);
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if (!nskb)
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return NULL;
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/* This is a large skb, set destructor callback to release head */
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if (is_vmalloc_addr(skb->head))
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nskb->destructor = skb->destructor;
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return nskb;
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}
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/*
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* skb should fit one page. This choice is good for headerless malloc.
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* But we should limit to 8K so that userspace does not have to
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* use enormous buffer sizes on recvmsg() calls just to avoid
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* MSG_TRUNC when PAGE_SIZE is very large.
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*/
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#if PAGE_SIZE < 8192UL
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#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(PAGE_SIZE)
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#else
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#define NLMSG_GOODSIZE SKB_WITH_OVERHEAD(8192UL)
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#endif
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#define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)
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struct netlink_callback {
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struct sk_buff *skb;
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const struct nlmsghdr *nlh;
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int (*dump)(struct sk_buff * skb,
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struct netlink_callback *cb);
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int (*done)(struct netlink_callback *cb);
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void *data;
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/* the module that dump function belong to */
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struct module *module;
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struct netlink_ext_ack *extack;
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u16 family;
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u16 answer_flags;
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u32 min_dump_alloc;
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unsigned int prev_seq, seq;
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int flags;
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bool strict_check;
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union {
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u8 ctx[48];
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/* args is deprecated. Cast a struct over ctx instead
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* for proper type safety.
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*/
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long args[6];
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};
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};
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#define NL_ASSERT_DUMP_CTX_FITS(type_name) \
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BUILD_BUG_ON(sizeof(type_name) > \
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sizeof_field(struct netlink_callback, ctx))
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struct netlink_notify {
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struct net *net;
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u32 portid;
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int protocol;
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};
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struct nlmsghdr *
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__nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);
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struct netlink_dump_control {
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int (*start)(struct netlink_callback *);
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int (*dump)(struct sk_buff *skb, struct netlink_callback *);
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int (*done)(struct netlink_callback *);
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struct netlink_ext_ack *extack;
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void *data;
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struct module *module;
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u32 min_dump_alloc;
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int flags;
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};
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int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
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const struct nlmsghdr *nlh,
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struct netlink_dump_control *control);
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static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
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const struct nlmsghdr *nlh,
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struct netlink_dump_control *control)
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{
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if (!control->module)
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control->module = THIS_MODULE;
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return __netlink_dump_start(ssk, skb, nlh, control);
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}
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struct netlink_tap {
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struct net_device *dev;
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struct module *module;
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struct list_head list;
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};
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int netlink_add_tap(struct netlink_tap *nt);
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int netlink_remove_tap(struct netlink_tap *nt);
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bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
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struct user_namespace *ns, int cap);
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bool netlink_ns_capable(const struct sk_buff *skb,
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struct user_namespace *ns, int cap);
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bool netlink_capable(const struct sk_buff *skb, int cap);
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bool netlink_net_capable(const struct sk_buff *skb, int cap);
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struct sk_buff *netlink_alloc_large_skb(unsigned int size, int broadcast);
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#endif /* __LINUX_NETLINK_H */
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