linux/include/net/if_inet6.h
Gustavo A. R. Silva 0fa39d6dd0 ipv6: Replace zero-length array with flexible-array
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-05-11 13:18:54 -07:00

262 lines
5.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* inet6 interface/address list definitions
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <roque@di.fc.ul.pt>
*/
#ifndef _NET_IF_INET6_H
#define _NET_IF_INET6_H
#include <net/snmp.h>
#include <linux/ipv6.h>
#include <linux/refcount.h>
/* inet6_dev.if_flags */
#define IF_RA_OTHERCONF 0x80
#define IF_RA_MANAGED 0x40
#define IF_RA_RCVD 0x20
#define IF_RS_SENT 0x10
#define IF_READY 0x80000000
/* prefix flags */
#define IF_PREFIX_ONLINK 0x01
#define IF_PREFIX_AUTOCONF 0x02
enum {
INET6_IFADDR_STATE_PREDAD,
INET6_IFADDR_STATE_DAD,
INET6_IFADDR_STATE_POSTDAD,
INET6_IFADDR_STATE_ERRDAD,
INET6_IFADDR_STATE_DEAD,
};
struct inet6_ifaddr {
struct in6_addr addr;
__u32 prefix_len;
__u32 rt_priority;
/* In seconds, relative to tstamp. Expiry is at tstamp + HZ * lft. */
__u32 valid_lft;
__u32 prefered_lft;
refcount_t refcnt;
spinlock_t lock;
int state;
__u32 flags;
__u8 dad_probes;
__u8 stable_privacy_retry;
__u16 scope;
__u64 dad_nonce;
unsigned long cstamp; /* created timestamp */
unsigned long tstamp; /* updated timestamp */
struct delayed_work dad_work;
struct inet6_dev *idev;
struct fib6_info *rt;
struct hlist_node addr_lst;
struct list_head if_list;
struct list_head tmp_list;
struct inet6_ifaddr *ifpub;
int regen_count;
bool tokenized;
struct rcu_head rcu;
struct in6_addr peer_addr;
};
struct ip6_sf_socklist {
unsigned int sl_max;
unsigned int sl_count;
struct in6_addr sl_addr[];
};
#define IP6_SFLSIZE(count) (sizeof(struct ip6_sf_socklist) + \
(count) * sizeof(struct in6_addr))
#define IP6_SFBLOCK 10 /* allocate this many at once */
struct ipv6_mc_socklist {
struct in6_addr addr;
int ifindex;
unsigned int sfmode; /* MCAST_{INCLUDE,EXCLUDE} */
struct ipv6_mc_socklist __rcu *next;
rwlock_t sflock;
struct ip6_sf_socklist *sflist;
struct rcu_head rcu;
};
struct ip6_sf_list {
struct ip6_sf_list *sf_next;
struct in6_addr sf_addr;
unsigned long sf_count[2]; /* include/exclude counts */
unsigned char sf_gsresp; /* include in g & s response? */
unsigned char sf_oldin; /* change state */
unsigned char sf_crcount; /* retrans. left to send */
};
#define MAF_TIMER_RUNNING 0x01
#define MAF_LAST_REPORTER 0x02
#define MAF_LOADED 0x04
#define MAF_NOREPORT 0x08
#define MAF_GSQUERY 0x10
struct ifmcaddr6 {
struct in6_addr mca_addr;
struct inet6_dev *idev;
struct ifmcaddr6 *next;
struct ip6_sf_list *mca_sources;
struct ip6_sf_list *mca_tomb;
unsigned int mca_sfmode;
unsigned char mca_crcount;
unsigned long mca_sfcount[2];
struct timer_list mca_timer;
unsigned int mca_flags;
int mca_users;
refcount_t mca_refcnt;
spinlock_t mca_lock;
unsigned long mca_cstamp;
unsigned long mca_tstamp;
};
/* Anycast stuff */
struct ipv6_ac_socklist {
struct in6_addr acl_addr;
int acl_ifindex;
struct ipv6_ac_socklist *acl_next;
};
struct ifacaddr6 {
struct in6_addr aca_addr;
struct fib6_info *aca_rt;
struct ifacaddr6 *aca_next;
struct hlist_node aca_addr_lst;
int aca_users;
refcount_t aca_refcnt;
unsigned long aca_cstamp;
unsigned long aca_tstamp;
struct rcu_head rcu;
};
#define IFA_HOST IPV6_ADDR_LOOPBACK
#define IFA_LINK IPV6_ADDR_LINKLOCAL
#define IFA_SITE IPV6_ADDR_SITELOCAL
struct ipv6_devstat {
struct proc_dir_entry *proc_dir_entry;
DEFINE_SNMP_STAT(struct ipstats_mib, ipv6);
DEFINE_SNMP_STAT_ATOMIC(struct icmpv6_mib_device, icmpv6dev);
DEFINE_SNMP_STAT_ATOMIC(struct icmpv6msg_mib_device, icmpv6msgdev);
};
struct inet6_dev {
struct net_device *dev;
struct list_head addr_list;
struct ifmcaddr6 *mc_list;
struct ifmcaddr6 *mc_tomb;
spinlock_t mc_lock;
unsigned char mc_qrv; /* Query Robustness Variable */
unsigned char mc_gq_running;
unsigned char mc_ifc_count;
unsigned char mc_dad_count;
unsigned long mc_v1_seen; /* Max time we stay in MLDv1 mode */
unsigned long mc_qi; /* Query Interval */
unsigned long mc_qri; /* Query Response Interval */
unsigned long mc_maxdelay;
struct timer_list mc_gq_timer; /* general query timer */
struct timer_list mc_ifc_timer; /* interface change timer */
struct timer_list mc_dad_timer; /* dad complete mc timer */
struct ifacaddr6 *ac_list;
rwlock_t lock;
refcount_t refcnt;
__u32 if_flags;
int dead;
u32 desync_factor;
struct list_head tempaddr_list;
struct in6_addr token;
struct neigh_parms *nd_parms;
struct ipv6_devconf cnf;
struct ipv6_devstat stats;
struct timer_list rs_timer;
__s32 rs_interval; /* in jiffies */
__u8 rs_probes;
unsigned long tstamp; /* ipv6InterfaceTable update timestamp */
struct rcu_head rcu;
};
static inline void ipv6_eth_mc_map(const struct in6_addr *addr, char *buf)
{
/*
* +-------+-------+-------+-------+-------+-------+
* | 33 | 33 | DST13 | DST14 | DST15 | DST16 |
* +-------+-------+-------+-------+-------+-------+
*/
buf[0]= 0x33;
buf[1]= 0x33;
memcpy(buf + 2, &addr->s6_addr32[3], sizeof(__u32));
}
static inline void ipv6_arcnet_mc_map(const struct in6_addr *addr, char *buf)
{
buf[0] = 0x00;
}
static inline void ipv6_ib_mc_map(const struct in6_addr *addr,
const unsigned char *broadcast, char *buf)
{
unsigned char scope = broadcast[5] & 0xF;
buf[0] = 0; /* Reserved */
buf[1] = 0xff; /* Multicast QPN */
buf[2] = 0xff;
buf[3] = 0xff;
buf[4] = 0xff;
buf[5] = 0x10 | scope; /* scope from broadcast address */
buf[6] = 0x60; /* IPv6 signature */
buf[7] = 0x1b;
buf[8] = broadcast[8]; /* P_Key */
buf[9] = broadcast[9];
memcpy(buf + 10, addr->s6_addr + 6, 10);
}
static inline int ipv6_ipgre_mc_map(const struct in6_addr *addr,
const unsigned char *broadcast, char *buf)
{
if ((broadcast[0] | broadcast[1] | broadcast[2] | broadcast[3]) != 0) {
memcpy(buf, broadcast, 4);
} else {
/* v4mapped? */
if ((addr->s6_addr32[0] | addr->s6_addr32[1] |
(addr->s6_addr32[2] ^ htonl(0x0000ffff))) != 0)
return -EINVAL;
memcpy(buf, &addr->s6_addr32[3], 4);
}
return 0;
}
#endif