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