linux/include/net/ip.h
Nicolas Dichtel e622502c31 ipmr: fix kernel panic when forwarding mcast packets
The stacktrace was:
[   86.305548] BUG: kernel NULL pointer dereference, address: 0000000000000092
[   86.306815] #PF: supervisor read access in kernel mode
[   86.307717] #PF: error_code(0x0000) - not-present page
[   86.308624] PGD 0 P4D 0
[   86.309091] Oops: 0000 [#1] PREEMPT SMP NOPTI
[   86.309883] CPU: 2 PID: 3139 Comm: pimd Tainted: G     U             6.8.0-6wind-knet #1
[   86.311027] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.1-0-g0551a4be2c-prebuilt.qemu-project.org 04/01/2014
[   86.312728] RIP: 0010:ip_mr_forward (/build/work/knet/net/ipv4/ipmr.c:1985)
[ 86.313399] Code: f9 1f 0f 87 85 03 00 00 48 8d 04 5b 48 8d 04 83 49 8d 44 c5 00 48 8b 40 70 48 39 c2 0f 84 d9 00 00 00 49 8b 46 58 48 83 e0 fe <80> b8 92 00 00 00 00 0f 84 55 ff ff ff 49 83 47 38 01 45 85 e4 0f
[   86.316565] RSP: 0018:ffffad21c0583ae0 EFLAGS: 00010246
[   86.317497] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   86.318596] RDX: ffff9559cb46c000 RSI: 0000000000000000 RDI: 0000000000000000
[   86.319627] RBP: ffffad21c0583b30 R08: 0000000000000000 R09: 0000000000000000
[   86.320650] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
[   86.321672] R13: ffff9559c093a000 R14: ffff9559cc00b800 R15: ffff9559c09c1d80
[   86.322873] FS:  00007f85db661980(0000) GS:ffff955a79d00000(0000) knlGS:0000000000000000
[   86.324291] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   86.325314] CR2: 0000000000000092 CR3: 000000002f13a000 CR4: 0000000000350ef0
[   86.326589] Call Trace:
[   86.327036]  <TASK>
[   86.327434] ? show_regs (/build/work/knet/arch/x86/kernel/dumpstack.c:479)
[   86.328049] ? __die (/build/work/knet/arch/x86/kernel/dumpstack.c:421 /build/work/knet/arch/x86/kernel/dumpstack.c:434)
[   86.328508] ? page_fault_oops (/build/work/knet/arch/x86/mm/fault.c:707)
[   86.329107] ? do_user_addr_fault (/build/work/knet/arch/x86/mm/fault.c:1264)
[   86.329756] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.330350] ? __irq_work_queue_local (/build/work/knet/kernel/irq_work.c:111 (discriminator 1))
[   86.331013] ? exc_page_fault (/build/work/knet/./arch/x86/include/asm/paravirt.h:693 /build/work/knet/arch/x86/mm/fault.c:1515 /build/work/knet/arch/x86/mm/fault.c:1563)
[   86.331702] ? asm_exc_page_fault (/build/work/knet/./arch/x86/include/asm/idtentry.h:570)
[   86.332468] ? ip_mr_forward (/build/work/knet/net/ipv4/ipmr.c:1985)
[   86.333183] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.333920] ipmr_mfc_add (/build/work/knet/./include/linux/rcupdate.h:782 /build/work/knet/net/ipv4/ipmr.c:1009 /build/work/knet/net/ipv4/ipmr.c:1273)
[   86.334583] ? __pfx_ipmr_hash_cmp (/build/work/knet/net/ipv4/ipmr.c:363)
[   86.335357] ip_mroute_setsockopt (/build/work/knet/net/ipv4/ipmr.c:1470)
[   86.336135] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.336854] ? ip_mroute_setsockopt (/build/work/knet/net/ipv4/ipmr.c:1470)
[   86.337679] do_ip_setsockopt (/build/work/knet/net/ipv4/ip_sockglue.c:944)
[   86.338408] ? __pfx_unix_stream_read_actor (/build/work/knet/net/unix/af_unix.c:2862)
[   86.339232] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.339809] ? aa_sk_perm (/build/work/knet/security/apparmor/include/cred.h:153 /build/work/knet/security/apparmor/net.c:181)
[   86.340342] ip_setsockopt (/build/work/knet/net/ipv4/ip_sockglue.c:1415)
[   86.340859] raw_setsockopt (/build/work/knet/net/ipv4/raw.c:836)
[   86.341408] ? security_socket_setsockopt (/build/work/knet/security/security.c:4561 (discriminator 13))
[   86.342116] sock_common_setsockopt (/build/work/knet/net/core/sock.c:3716)
[   86.342747] do_sock_setsockopt (/build/work/knet/net/socket.c:2313)
[   86.343363] __sys_setsockopt (/build/work/knet/./include/linux/file.h:32 /build/work/knet/net/socket.c:2336)
[   86.344020] __x64_sys_setsockopt (/build/work/knet/net/socket.c:2340)
[   86.344766] do_syscall_64 (/build/work/knet/arch/x86/entry/common.c:52 /build/work/knet/arch/x86/entry/common.c:83)
[   86.345433] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.346161] ? syscall_exit_work (/build/work/knet/./include/linux/audit.h:357 /build/work/knet/kernel/entry/common.c:160)
[   86.346938] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.347657] ? syscall_exit_to_user_mode (/build/work/knet/kernel/entry/common.c:215)
[   86.348538] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223)
[   86.349262] ? do_syscall_64 (/build/work/knet/./arch/x86/include/asm/cpufeature.h:171 /build/work/knet/arch/x86/entry/common.c:98)
[   86.349971] entry_SYSCALL_64_after_hwframe (/build/work/knet/arch/x86/entry/entry_64.S:129)

The original packet in ipmr_cache_report() may be queued and then forwarded
with ip_mr_forward(). This last function has the assumption that the skb
dst is set.

After the below commit, the skb dst is dropped by ipv4_pktinfo_prepare(),
which causes the oops.

Fixes: bb7403655b ("ipmr: support IP_PKTINFO on cache report IGMP msg")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240125141847.1931933-1-nicolas.dichtel@6wind.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-01-26 21:05:26 -08:00

822 lines
23 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* Definitions for the IP module.
*
* Version: @(#)ip.h 1.0.2 05/07/93
*
* Authors: Ross Biro
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Alan Cox, <gw4pts@gw4pts.ampr.org>
*
* Changes:
* Mike McLagan : Routing by source
*/
#ifndef _IP_H
#define _IP_H
#include <linux/types.h>
#include <linux/ip.h>
#include <linux/in.h>
#include <linux/skbuff.h>
#include <linux/jhash.h>
#include <linux/sockptr.h>
#include <linux/static_key.h>
#include <net/inet_sock.h>
#include <net/route.h>
#include <net/snmp.h>
#include <net/flow.h>
#include <net/flow_dissector.h>
#include <net/netns/hash.h>
#include <net/lwtunnel.h>
#define IPV4_MAX_PMTU 65535U /* RFC 2675, Section 5.1 */
#define IPV4_MIN_MTU 68 /* RFC 791 */
extern unsigned int sysctl_fib_sync_mem;
extern unsigned int sysctl_fib_sync_mem_min;
extern unsigned int sysctl_fib_sync_mem_max;
struct sock;
struct inet_skb_parm {
int iif;
struct ip_options opt; /* Compiled IP options */
u16 flags;
#define IPSKB_FORWARDED BIT(0)
#define IPSKB_XFRM_TUNNEL_SIZE BIT(1)
#define IPSKB_XFRM_TRANSFORMED BIT(2)
#define IPSKB_FRAG_COMPLETE BIT(3)
#define IPSKB_REROUTED BIT(4)
#define IPSKB_DOREDIRECT BIT(5)
#define IPSKB_FRAG_PMTU BIT(6)
#define IPSKB_L3SLAVE BIT(7)
#define IPSKB_NOPOLICY BIT(8)
#define IPSKB_MULTIPATH BIT(9)
u16 frag_max_size;
};
static inline bool ipv4_l3mdev_skb(u16 flags)
{
return !!(flags & IPSKB_L3SLAVE);
}
static inline unsigned int ip_hdrlen(const struct sk_buff *skb)
{
return ip_hdr(skb)->ihl * 4;
}
struct ipcm_cookie {
struct sockcm_cookie sockc;
__be32 addr;
int oif;
struct ip_options_rcu *opt;
__u8 protocol;
__u8 ttl;
__s16 tos;
char priority;
__u16 gso_size;
};
static inline void ipcm_init(struct ipcm_cookie *ipcm)
{
*ipcm = (struct ipcm_cookie) { .tos = -1 };
}
static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
const struct inet_sock *inet)
{
ipcm_init(ipcm);
ipcm->sockc.mark = READ_ONCE(inet->sk.sk_mark);
ipcm->sockc.tsflags = READ_ONCE(inet->sk.sk_tsflags);
ipcm->oif = READ_ONCE(inet->sk.sk_bound_dev_if);
ipcm->addr = inet->inet_saddr;
ipcm->protocol = inet->inet_num;
}
#define IPCB(skb) ((struct inet_skb_parm*)((skb)->cb))
#define PKTINFO_SKB_CB(skb) ((struct in_pktinfo *)((skb)->cb))
/* return enslaved device index if relevant */
static inline int inet_sdif(const struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
if (skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
return IPCB(skb)->iif;
#endif
return 0;
}
/* Special input handler for packets caught by router alert option.
They are selected only by protocol field, and then processed likely
local ones; but only if someone wants them! Otherwise, router
not running rsvpd will kill RSVP.
It is user level problem, what it will make with them.
I have no idea, how it will masquearde or NAT them (it is joke, joke :-)),
but receiver should be enough clever f.e. to forward mtrace requests,
sent to multicast group to reach destination designated router.
*/
struct ip_ra_chain {
struct ip_ra_chain __rcu *next;
struct sock *sk;
union {
void (*destructor)(struct sock *);
struct sock *saved_sk;
};
struct rcu_head rcu;
};
/* IP flags. */
#define IP_CE 0x8000 /* Flag: "Congestion" */
#define IP_DF 0x4000 /* Flag: "Don't Fragment" */
#define IP_MF 0x2000 /* Flag: "More Fragments" */
#define IP_OFFSET 0x1FFF /* "Fragment Offset" part */
#define IP_FRAG_TIME (30 * HZ) /* fragment lifetime */
struct msghdr;
struct net_device;
struct packet_type;
struct rtable;
struct sockaddr;
int igmp_mc_init(void);
/*
* Functions provided by ip.c
*/
int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
__be32 saddr, __be32 daddr,
struct ip_options_rcu *opt, u8 tos);
int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,
struct net_device *orig_dev);
void ip_list_rcv(struct list_head *head, struct packet_type *pt,
struct net_device *orig_dev);
int ip_local_deliver(struct sk_buff *skb);
void ip_protocol_deliver_rcu(struct net *net, struct sk_buff *skb, int proto);
int ip_mr_input(struct sk_buff *skb);
int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb);
int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb);
int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
int (*output)(struct net *, struct sock *, struct sk_buff *));
struct ip_fraglist_iter {
struct sk_buff *frag;
struct iphdr *iph;
int offset;
unsigned int hlen;
};
void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph,
unsigned int hlen, struct ip_fraglist_iter *iter);
void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter);
static inline struct sk_buff *ip_fraglist_next(struct ip_fraglist_iter *iter)
{
struct sk_buff *skb = iter->frag;
iter->frag = skb->next;
skb_mark_not_on_list(skb);
return skb;
}
struct ip_frag_state {
bool DF;
unsigned int hlen;
unsigned int ll_rs;
unsigned int mtu;
unsigned int left;
int offset;
int ptr;
__be16 not_last_frag;
};
void ip_frag_init(struct sk_buff *skb, unsigned int hlen, unsigned int ll_rs,
unsigned int mtu, bool DF, struct ip_frag_state *state);
struct sk_buff *ip_frag_next(struct sk_buff *skb,
struct ip_frag_state *state);
void ip_send_check(struct iphdr *ip);
int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb);
int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
__u8 tos);
void ip_init(void);
int ip_append_data(struct sock *sk, struct flowi4 *fl4,
int getfrag(void *from, char *to, int offset, int len,
int odd, struct sk_buff *skb),
void *from, int len, int protolen,
struct ipcm_cookie *ipc,
struct rtable **rt,
unsigned int flags);
int ip_generic_getfrag(void *from, char *to, int offset, int len, int odd,
struct sk_buff *skb);
struct sk_buff *__ip_make_skb(struct sock *sk, struct flowi4 *fl4,
struct sk_buff_head *queue,
struct inet_cork *cork);
int ip_send_skb(struct net *net, struct sk_buff *skb);
int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4);
void ip_flush_pending_frames(struct sock *sk);
struct sk_buff *ip_make_skb(struct sock *sk, struct flowi4 *fl4,
int getfrag(void *from, char *to, int offset,
int len, int odd, struct sk_buff *skb),
void *from, int length, int transhdrlen,
struct ipcm_cookie *ipc, struct rtable **rtp,
struct inet_cork *cork, unsigned int flags);
int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
static inline struct sk_buff *ip_finish_skb(struct sock *sk, struct flowi4 *fl4)
{
return __ip_make_skb(sk, fl4, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
}
/* Get the route scope that should be used when sending a packet. */
static inline u8 ip_sendmsg_scope(const struct inet_sock *inet,
const struct ipcm_cookie *ipc,
const struct msghdr *msg)
{
if (sock_flag(&inet->sk, SOCK_LOCALROUTE) ||
msg->msg_flags & MSG_DONTROUTE ||
(ipc->opt && ipc->opt->opt.is_strictroute))
return RT_SCOPE_LINK;
return RT_SCOPE_UNIVERSE;
}
static inline __u8 get_rttos(struct ipcm_cookie* ipc, struct inet_sock *inet)
{
return (ipc->tos != -1) ? RT_TOS(ipc->tos) : RT_TOS(READ_ONCE(inet->tos));
}
/* datagram.c */
int __ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
int ip4_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
void ip4_datagram_release_cb(struct sock *sk);
struct ip_reply_arg {
struct kvec iov[1];
int flags;
__wsum csum;
int csumoffset; /* u16 offset of csum in iov[0].iov_base */
/* -1 if not needed */
int bound_dev_if;
u8 tos;
kuid_t uid;
};
#define IP_REPLY_ARG_NOSRCCHECK 1
static inline __u8 ip_reply_arg_flowi_flags(const struct ip_reply_arg *arg)
{
return (arg->flags & IP_REPLY_ARG_NOSRCCHECK) ? FLOWI_FLAG_ANYSRC : 0;
}
void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
const struct ip_options *sopt,
__be32 daddr, __be32 saddr,
const struct ip_reply_arg *arg,
unsigned int len, u64 transmit_time, u32 txhash);
#define IP_INC_STATS(net, field) SNMP_INC_STATS64((net)->mib.ip_statistics, field)
#define __IP_INC_STATS(net, field) __SNMP_INC_STATS64((net)->mib.ip_statistics, field)
#define IP_ADD_STATS(net, field, val) SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
#define __IP_ADD_STATS(net, field, val) __SNMP_ADD_STATS64((net)->mib.ip_statistics, field, val)
#define IP_UPD_PO_STATS(net, field, val) SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
#define __IP_UPD_PO_STATS(net, field, val) __SNMP_UPD_PO_STATS64((net)->mib.ip_statistics, field, val)
#define NET_INC_STATS(net, field) SNMP_INC_STATS((net)->mib.net_statistics, field)
#define __NET_INC_STATS(net, field) __SNMP_INC_STATS((net)->mib.net_statistics, field)
#define NET_ADD_STATS(net, field, adnd) SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
#define __NET_ADD_STATS(net, field, adnd) __SNMP_ADD_STATS((net)->mib.net_statistics, field, adnd)
static inline u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offt)
{
return *(((unsigned long *)per_cpu_ptr(mib, cpu)) + offt);
}
unsigned long snmp_fold_field(void __percpu *mib, int offt);
#if BITS_PER_LONG==32
u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
size_t syncp_offset);
u64 snmp_fold_field64(void __percpu *mib, int offt, size_t sync_off);
#else
static inline u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offct,
size_t syncp_offset)
{
return snmp_get_cpu_field(mib, cpu, offct);
}
static inline u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_off)
{
return snmp_fold_field(mib, offt);
}
#endif
#define snmp_get_cpu_field64_batch(buff64, stats_list, mib_statistic, offset) \
{ \
int i, c; \
for_each_possible_cpu(c) { \
for (i = 0; stats_list[i].name; i++) \
buff64[i] += snmp_get_cpu_field64( \
mib_statistic, \
c, stats_list[i].entry, \
offset); \
} \
}
#define snmp_get_cpu_field_batch(buff, stats_list, mib_statistic) \
{ \
int i, c; \
for_each_possible_cpu(c) { \
for (i = 0; stats_list[i].name; i++) \
buff[i] += snmp_get_cpu_field( \
mib_statistic, \
c, stats_list[i].entry); \
} \
}
static inline void inet_get_local_port_range(const struct net *net, int *low, int *high)
{
u32 range = READ_ONCE(net->ipv4.ip_local_ports.range);
*low = range & 0xffff;
*high = range >> 16;
}
bool inet_sk_get_local_port_range(const struct sock *sk, int *low, int *high);
#ifdef CONFIG_SYSCTL
static inline bool inet_is_local_reserved_port(struct net *net, unsigned short port)
{
if (!net->ipv4.sysctl_local_reserved_ports)
return false;
return test_bit(port, net->ipv4.sysctl_local_reserved_ports);
}
static inline bool sysctl_dev_name_is_allowed(const char *name)
{
return strcmp(name, "default") != 0 && strcmp(name, "all") != 0;
}
static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
{
return port < READ_ONCE(net->ipv4.sysctl_ip_prot_sock);
}
#else
static inline bool inet_is_local_reserved_port(struct net *net, unsigned short port)
{
return false;
}
static inline bool inet_port_requires_bind_service(struct net *net, unsigned short port)
{
return port < PROT_SOCK;
}
#endif
__be32 inet_current_timestamp(void);
/* From inetpeer.c */
extern int inet_peer_threshold;
extern int inet_peer_minttl;
extern int inet_peer_maxttl;
void ipfrag_init(void);
void ip_static_sysctl_init(void);
#define IP4_REPLY_MARK(net, mark) \
(READ_ONCE((net)->ipv4.sysctl_fwmark_reflect) ? (mark) : 0)
static inline bool ip_is_fragment(const struct iphdr *iph)
{
return (iph->frag_off & htons(IP_MF | IP_OFFSET)) != 0;
}
#ifdef CONFIG_INET
#include <net/dst.h>
/* The function in 2.2 was invalid, producing wrong result for
* check=0xFEFF. It was noticed by Arthur Skawina _year_ ago. --ANK(000625) */
static inline
int ip_decrease_ttl(struct iphdr *iph)
{
u32 check = (__force u32)iph->check;
check += (__force u32)htons(0x0100);
iph->check = (__force __sum16)(check + (check>=0xFFFF));
return --iph->ttl;
}
static inline int ip_mtu_locked(const struct dst_entry *dst)
{
const struct rtable *rt = (const struct rtable *)dst;
return rt->rt_mtu_locked || dst_metric_locked(dst, RTAX_MTU);
}
static inline
int ip_dont_fragment(const struct sock *sk, const struct dst_entry *dst)
{
u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
return pmtudisc == IP_PMTUDISC_DO ||
(pmtudisc == IP_PMTUDISC_WANT &&
!ip_mtu_locked(dst));
}
static inline bool ip_sk_accept_pmtu(const struct sock *sk)
{
u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
return pmtudisc != IP_PMTUDISC_INTERFACE &&
pmtudisc != IP_PMTUDISC_OMIT;
}
static inline bool ip_sk_use_pmtu(const struct sock *sk)
{
return READ_ONCE(inet_sk(sk)->pmtudisc) < IP_PMTUDISC_PROBE;
}
static inline bool ip_sk_ignore_df(const struct sock *sk)
{
u8 pmtudisc = READ_ONCE(inet_sk(sk)->pmtudisc);
return pmtudisc < IP_PMTUDISC_DO || pmtudisc == IP_PMTUDISC_OMIT;
}
static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst,
bool forwarding)
{
const struct rtable *rt = container_of(dst, struct rtable, dst);
struct net *net = dev_net(dst->dev);
unsigned int mtu;
if (READ_ONCE(net->ipv4.sysctl_ip_fwd_use_pmtu) ||
ip_mtu_locked(dst) ||
!forwarding) {
mtu = rt->rt_pmtu;
if (mtu && time_before(jiffies, rt->dst.expires))
goto out;
}
/* 'forwarding = true' case should always honour route mtu */
mtu = dst_metric_raw(dst, RTAX_MTU);
if (mtu)
goto out;
mtu = READ_ONCE(dst->dev->mtu);
if (unlikely(ip_mtu_locked(dst))) {
if (rt->rt_uses_gateway && mtu > 576)
mtu = 576;
}
out:
mtu = min_t(unsigned int, mtu, IP_MAX_MTU);
return mtu - lwtunnel_headroom(dst->lwtstate, mtu);
}
static inline unsigned int ip_skb_dst_mtu(struct sock *sk,
const struct sk_buff *skb)
{
unsigned int mtu;
if (!sk || !sk_fullsock(sk) || ip_sk_use_pmtu(sk)) {
bool forwarding = IPCB(skb)->flags & IPSKB_FORWARDED;
return ip_dst_mtu_maybe_forward(skb_dst(skb), forwarding);
}
mtu = min(READ_ONCE(skb_dst(skb)->dev->mtu), IP_MAX_MTU);
return mtu - lwtunnel_headroom(skb_dst(skb)->lwtstate, mtu);
}
struct dst_metrics *ip_fib_metrics_init(struct net *net, struct nlattr *fc_mx,
int fc_mx_len,
struct netlink_ext_ack *extack);
static inline void ip_fib_metrics_put(struct dst_metrics *fib_metrics)
{
if (fib_metrics != &dst_default_metrics &&
refcount_dec_and_test(&fib_metrics->refcnt))
kfree(fib_metrics);
}
/* ipv4 and ipv6 both use refcounted metrics if it is not the default */
static inline
void ip_dst_init_metrics(struct dst_entry *dst, struct dst_metrics *fib_metrics)
{
dst_init_metrics(dst, fib_metrics->metrics, true);
if (fib_metrics != &dst_default_metrics) {
dst->_metrics |= DST_METRICS_REFCOUNTED;
refcount_inc(&fib_metrics->refcnt);
}
}
static inline
void ip_dst_metrics_put(struct dst_entry *dst)
{
struct dst_metrics *p = (struct dst_metrics *)DST_METRICS_PTR(dst);
if (p != &dst_default_metrics && refcount_dec_and_test(&p->refcnt))
kfree(p);
}
void __ip_select_ident(struct net *net, struct iphdr *iph, int segs);
static inline void ip_select_ident_segs(struct net *net, struct sk_buff *skb,
struct sock *sk, int segs)
{
struct iphdr *iph = ip_hdr(skb);
/* We had many attacks based on IPID, use the private
* generator as much as we can.
*/
if (sk && inet_sk(sk)->inet_daddr) {
int val;
/* avoid atomic operations for TCP,
* as we hold socket lock at this point.
*/
if (sk_is_tcp(sk)) {
sock_owned_by_me(sk);
val = atomic_read(&inet_sk(sk)->inet_id);
atomic_set(&inet_sk(sk)->inet_id, val + segs);
} else {
val = atomic_add_return(segs, &inet_sk(sk)->inet_id);
}
iph->id = htons(val);
return;
}
if ((iph->frag_off & htons(IP_DF)) && !skb->ignore_df) {
iph->id = 0;
} else {
/* Unfortunately we need the big hammer to get a suitable IPID */
__ip_select_ident(net, iph, segs);
}
}
static inline void ip_select_ident(struct net *net, struct sk_buff *skb,
struct sock *sk)
{
ip_select_ident_segs(net, skb, sk, 1);
}
static inline __wsum inet_compute_pseudo(struct sk_buff *skb, int proto)
{
return csum_tcpudp_nofold(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
skb->len, proto, 0);
}
/* copy IPv4 saddr & daddr to flow_keys, possibly using 64bit load/store
* Equivalent to : flow->v4addrs.src = iph->saddr;
* flow->v4addrs.dst = iph->daddr;
*/
static inline void iph_to_flow_copy_v4addrs(struct flow_keys *flow,
const struct iphdr *iph)
{
BUILD_BUG_ON(offsetof(typeof(flow->addrs), v4addrs.dst) !=
offsetof(typeof(flow->addrs), v4addrs.src) +
sizeof(flow->addrs.v4addrs.src));
memcpy(&flow->addrs.v4addrs, &iph->addrs, sizeof(flow->addrs.v4addrs));
flow->control.addr_type = FLOW_DISSECTOR_KEY_IPV4_ADDRS;
}
/*
* Map a multicast IP onto multicast MAC for type ethernet.
*/
static inline void ip_eth_mc_map(__be32 naddr, char *buf)
{
__u32 addr=ntohl(naddr);
buf[0]=0x01;
buf[1]=0x00;
buf[2]=0x5e;
buf[5]=addr&0xFF;
addr>>=8;
buf[4]=addr&0xFF;
addr>>=8;
buf[3]=addr&0x7F;
}
/*
* Map a multicast IP onto multicast MAC for type IP-over-InfiniBand.
* Leave P_Key as 0 to be filled in by driver.
*/
static inline void ip_ib_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
{
__u32 addr;
unsigned char scope = broadcast[5] & 0xF;
buf[0] = 0; /* Reserved */
buf[1] = 0xff; /* Multicast QPN */
buf[2] = 0xff;
buf[3] = 0xff;
addr = ntohl(naddr);
buf[4] = 0xff;
buf[5] = 0x10 | scope; /* scope from broadcast address */
buf[6] = 0x40; /* IPv4 signature */
buf[7] = 0x1b;
buf[8] = broadcast[8]; /* P_Key */
buf[9] = broadcast[9];
buf[10] = 0;
buf[11] = 0;
buf[12] = 0;
buf[13] = 0;
buf[14] = 0;
buf[15] = 0;
buf[19] = addr & 0xff;
addr >>= 8;
buf[18] = addr & 0xff;
addr >>= 8;
buf[17] = addr & 0xff;
addr >>= 8;
buf[16] = addr & 0x0f;
}
static inline void ip_ipgre_mc_map(__be32 naddr, const unsigned char *broadcast, char *buf)
{
if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0)
memcpy(buf, broadcast, 4);
else
memcpy(buf, &naddr, sizeof(naddr));
}
#if IS_ENABLED(CONFIG_IPV6)
#include <linux/ipv6.h>
#endif
static __inline__ void inet_reset_saddr(struct sock *sk)
{
inet_sk(sk)->inet_rcv_saddr = inet_sk(sk)->inet_saddr = 0;
#if IS_ENABLED(CONFIG_IPV6)
if (sk->sk_family == PF_INET6) {
struct ipv6_pinfo *np = inet6_sk(sk);
memset(&np->saddr, 0, sizeof(np->saddr));
memset(&sk->sk_v6_rcv_saddr, 0, sizeof(sk->sk_v6_rcv_saddr));
}
#endif
}
#endif
static inline unsigned int ipv4_addr_hash(__be32 ip)
{
return (__force unsigned int) ip;
}
static inline u32 ipv4_portaddr_hash(const struct net *net,
__be32 saddr,
unsigned int port)
{
return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
}
bool ip_call_ra_chain(struct sk_buff *skb);
/*
* Functions provided by ip_fragment.c
*/
enum ip_defrag_users {
IP_DEFRAG_LOCAL_DELIVER,
IP_DEFRAG_CALL_RA_CHAIN,
IP_DEFRAG_CONNTRACK_IN,
__IP_DEFRAG_CONNTRACK_IN_END = IP_DEFRAG_CONNTRACK_IN + USHRT_MAX,
IP_DEFRAG_CONNTRACK_OUT,
__IP_DEFRAG_CONNTRACK_OUT_END = IP_DEFRAG_CONNTRACK_OUT + USHRT_MAX,
IP_DEFRAG_CONNTRACK_BRIDGE_IN,
__IP_DEFRAG_CONNTRACK_BRIDGE_IN = IP_DEFRAG_CONNTRACK_BRIDGE_IN + USHRT_MAX,
IP_DEFRAG_VS_IN,
IP_DEFRAG_VS_OUT,
IP_DEFRAG_VS_FWD,
IP_DEFRAG_AF_PACKET,
IP_DEFRAG_MACVLAN,
};
/* Return true if the value of 'user' is between 'lower_bond'
* and 'upper_bond' inclusively.
*/
static inline bool ip_defrag_user_in_between(u32 user,
enum ip_defrag_users lower_bond,
enum ip_defrag_users upper_bond)
{
return user >= lower_bond && user <= upper_bond;
}
int ip_defrag(struct net *net, struct sk_buff *skb, u32 user);
#ifdef CONFIG_INET
struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user);
#else
static inline struct sk_buff *ip_check_defrag(struct net *net, struct sk_buff *skb, u32 user)
{
return skb;
}
#endif
/*
* Functions provided by ip_forward.c
*/
int ip_forward(struct sk_buff *skb);
/*
* Functions provided by ip_options.c
*/
void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
__be32 daddr, struct rtable *rt);
int __ip_options_echo(struct net *net, struct ip_options *dopt,
struct sk_buff *skb, const struct ip_options *sopt);
static inline int ip_options_echo(struct net *net, struct ip_options *dopt,
struct sk_buff *skb)
{
return __ip_options_echo(net, dopt, skb, &IPCB(skb)->opt);
}
void ip_options_fragment(struct sk_buff *skb);
int __ip_options_compile(struct net *net, struct ip_options *opt,
struct sk_buff *skb, __be32 *info);
int ip_options_compile(struct net *net, struct ip_options *opt,
struct sk_buff *skb);
int ip_options_get(struct net *net, struct ip_options_rcu **optp,
sockptr_t data, int optlen);
void ip_options_undo(struct ip_options *opt);
void ip_forward_options(struct sk_buff *skb);
int ip_options_rcv_srr(struct sk_buff *skb, struct net_device *dev);
/*
* Functions provided by ip_sockglue.c
*/
void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb, bool drop_dst);
void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
struct sk_buff *skb, int tlen, int offset);
int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
struct ipcm_cookie *ipc, bool allow_ipv6);
DECLARE_STATIC_KEY_FALSE(ip4_min_ttl);
int do_ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
unsigned int optlen);
int ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
unsigned int optlen);
int do_ip_getsockopt(struct sock *sk, int level, int optname,
sockptr_t optval, sockptr_t optlen);
int ip_getsockopt(struct sock *sk, int level, int optname, char __user *optval,
int __user *optlen);
int ip_ra_control(struct sock *sk, unsigned char on,
void (*destructor)(struct sock *));
int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len);
void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err, __be16 port,
u32 info, u8 *payload);
void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 dport,
u32 info);
static inline void ip_cmsg_recv(struct msghdr *msg, struct sk_buff *skb)
{
ip_cmsg_recv_offset(msg, skb->sk, skb, 0, 0);
}
bool icmp_global_allow(void);
extern int sysctl_icmp_msgs_per_sec;
extern int sysctl_icmp_msgs_burst;
#ifdef CONFIG_PROC_FS
int ip_misc_proc_init(void);
#endif
int rtm_getroute_parse_ip_proto(struct nlattr *attr, u8 *ip_proto, u8 family,
struct netlink_ext_ack *extack);
static inline bool inetdev_valid_mtu(unsigned int mtu)
{
return likely(mtu >= IPV4_MIN_MTU);
}
void ip_sock_set_freebind(struct sock *sk);
int ip_sock_set_mtu_discover(struct sock *sk, int val);
void ip_sock_set_pktinfo(struct sock *sk);
void ip_sock_set_recverr(struct sock *sk);
void ip_sock_set_tos(struct sock *sk, int val);
void __ip_sock_set_tos(struct sock *sk, int val);
#endif /* _IP_H */