/* SPDX-License-Identifier: GPL-2.0-or-later */ /* * Linux NET3: Internet Group Management Protocol [IGMP] * * Authors: * Alan Cox <alan@lxorguk.ukuu.org.uk> * * Extended to talk the BSD extended IGMP protocol of mrouted 3.6 */ #ifndef _LINUX_IGMP_H #define _LINUX_IGMP_H #include <linux/skbuff.h> #include <linux/timer.h> #include <linux/in.h> #include <linux/ip.h> #include <linux/refcount.h> #include <linux/sockptr.h> #include <uapi/linux/igmp.h> static inline struct igmphdr *igmp_hdr(const struct sk_buff *skb) { return (struct igmphdr *)skb_transport_header(skb); } static inline struct igmpv3_report * igmpv3_report_hdr(const struct sk_buff *skb) { return (struct igmpv3_report *)skb_transport_header(skb); } static inline struct igmpv3_query * igmpv3_query_hdr(const struct sk_buff *skb) { return (struct igmpv3_query *)skb_transport_header(skb); } struct ip_sf_socklist { unsigned int sl_max; unsigned int sl_count; struct rcu_head rcu; __be32 sl_addr[] __counted_by(sl_max); }; #define IP_SFBLOCK 10 /* allocate this many at once */ /* ip_mc_socklist is real list now. Speed is not argument; this list never used in fast path code */ struct ip_mc_socklist { struct ip_mc_socklist __rcu *next_rcu; struct ip_mreqn multi; unsigned int sfmode; /* MCAST_{INCLUDE,EXCLUDE} */ struct ip_sf_socklist __rcu *sflist; struct rcu_head rcu; }; struct ip_sf_list { struct ip_sf_list *sf_next; unsigned long sf_count[2]; /* include/exclude counts */ __be32 sf_inaddr; unsigned char sf_gsresp; /* include in g & s response? */ unsigned char sf_oldin; /* change state */ unsigned char sf_crcount; /* retrans. left to send */ }; struct ip_mc_list { struct in_device *interface; __be32 multiaddr; unsigned int sfmode; struct ip_sf_list *sources; struct ip_sf_list *tomb; unsigned long sfcount[2]; union { struct ip_mc_list *next; struct ip_mc_list __rcu *next_rcu; }; struct ip_mc_list __rcu *next_hash; struct timer_list timer; int users; refcount_t refcnt; spinlock_t lock; char tm_running; char reporter; char unsolicit_count; char loaded; unsigned char gsquery; /* check source marks? */ unsigned char crcount; unsigned long mca_cstamp; unsigned long mca_tstamp; struct rcu_head rcu; }; /* RFC3376, relevant sections: * - 4.1.1. Maximum Response Code * - 4.1.7. QQIC (Querier's Query Interval Code) * * For both MRC and QQIC, values >= 128 use the same floating-point * encoding as follows: * * 0 1 2 3 4 5 6 7 * +-+-+-+-+-+-+-+-+ * |1| exp | mant | * +-+-+-+-+-+-+-+-+ */ #define IGMPV3_FP_EXP(value) (((value) >> 4) & 0x07) #define IGMPV3_FP_MAN(value) ((value) & 0x0f) /* IGMPv3 floating-point exponential field min threshold */ #define IGMPV3_EXP_MIN_THRESHOLD 128 /* IGMPv3 FP max threshold (mant = 0xF, exp = 7) -> 31744 */ #define IGMPV3_EXP_MAX_THRESHOLD 31744 /* V3 exponential field encoding */ /* IGMPv3 MRC/QQIC 8-bit exponential field encode * * RFC3376, 4.1.1 & 4.1.7. defines only the decoding formula: * MRT/QQI = (mant | 0x10) << (exp + 3) * * but does NOT define the encoding procedure. To derive exponent: * * For any value of mantissa and exponent, the decoding formula * indicates that the "hidden bit" (0x10) is shifted 4 bits left * to sit above the 4-bit mantissa. The RFC again shifts this * entire block left by (exp + 3) to reconstruct the value. * So, 'hidden bit' is the MSB which is shifted by (4 + exp + 3). * * Total left shift of the 'hidden bit' = 4 + (exp + 3) = exp + 7. * This is the MSB at the 0-based bit position: (exp + 7). * Since fls() is 1-based, fls(value) - 1 = exp + 7. * * Therefore: * exp = fls(value) - 8 * mant = (value >> (exp + 3)) & 0x0F * * Final encoding formula: * 0x80 | (exp << 4) | mant * * Example (value = 3200): * 0 1 * 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * |0 0 0 0 1 1 0 0 1 0 0 0 0 0 0 0| (value = 3200) * | ^-^-mant^ ^..(exp+3)..^| exp = 4, mant = 9 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * Encoded: * 0x80 | (4 << 4) | 9 = 0xC9 */ static inline u8 igmpv3_exp_field_encode(unsigned long value) { u8 mc_exp, mc_man; /* MRC/QQIC < 128 is literal */ if (value < IGMPV3_EXP_MIN_THRESHOLD) return value; /* Saturate at max representable (mant = 0xF, exp = 7) -> 31744 */ if (value >= IGMPV3_EXP_MAX_THRESHOLD) return 0xFF; mc_exp = fls(value) - 8; mc_man = (value >> (mc_exp + 3)) & 0x0F; return 0x80 | (mc_exp << 4) | mc_man; } /* Calculate Maximum Response Code from Max Resp Time * * RFC3376, relevant sections: * - 4.1.1. Maximum Response Code * - 8.3. Query Response Interval * * MRC represents the encoded form of Max Resp Time (MRT); once * decoded, the resulting value is in units of 0.1 seconds (100 ms). */ static inline u8 igmpv3_mrc(unsigned long mrt) { return igmpv3_exp_field_encode(mrt); } /* Calculate Querier's Query Interval Code from Querier's Query Interval * * RFC3376, relevant sections: * - 4.1.7. QQIC (Querier's Query Interval Code) * - 8.2. Query Interval * - 8.12. Older Version Querier Present Timeout * (the [Query Interval] in the last Query received) * * QQIC represents the encoded form of Querier's Query Interval (QQI); * once decoded, the resulting value is in units of seconds. */ static inline u8 igmpv3_qqic(unsigned long qi) { return igmpv3_exp_field_encode(qi); } /* V3 exponential field decoding */ /* IGMPv3 MRC/QQIC 8-bit exponential field decode * * RFC3376, 4.1.1 & 4.1.7. defines the decoding formula: * 0 1 2 3 4 5 6 7 * +-+-+-+-+-+-+-+-+ * |1| exp | mant | * +-+-+-+-+-+-+-+-+ * Max Resp Time = (mant | 0x10) << (exp + 3) * QQI = (mant | 0x10) << (exp + 3) */ static inline unsigned long igmpv3_exp_field_decode(const u8 code) { if (code < IGMPV3_EXP_MIN_THRESHOLD) { return code; } else { unsigned long mc_man, mc_exp; mc_exp = IGMPV3_FP_EXP(code); mc_man = IGMPV3_FP_MAN(code); return (mc_man | 0x10) << (mc_exp + 3); } } /* Calculate Max Resp Time from Maximum Response Code * * RFC3376, relevant sections: * - 4.1.1. Maximum Response Code * - 8.3. Query Response Interval * * After decode, MRC represents the Maximum Response Time (MRT) in * units of 0.1 seconds (100 ms). */ static inline unsigned long igmpv3_mrt(const struct igmpv3_query *ih3) { return igmpv3_exp_field_decode(ih3->code); } /* Calculate Querier's Query Interval from Querier's Query Interval Code * * RFC3376, relevant sections: * - 4.1.7. QQIC (Querier's Query Interval Code) * - 8.2. Query Interval * - 8.12. Older Version Querier Present Timeout * (the [Query Interval] in the last Query received) * * After decode, QQIC represents the Querier's Query Interval in units * of seconds. */ static inline unsigned long igmpv3_qqi(const struct igmpv3_query *ih3) { return igmpv3_exp_field_decode(ih3->qqic); } static inline int ip_mc_may_pull(struct sk_buff *skb, unsigned int len) { if (skb_transport_offset(skb) + ip_transport_len(skb) < len) return 0; return pskb_may_pull(skb, len); } extern int ip_check_mc_rcu(struct in_device *dev, __be32 mc_addr, __be32 src_addr, u8 proto); extern int igmp_rcv(struct sk_buff *); extern int ip_mc_join_group(struct sock *sk, struct ip_mreqn *imr); extern int ip_mc_join_group_ssm(struct sock *sk, struct ip_mreqn *imr, unsigned int mode); extern int ip_mc_leave_group(struct sock *sk, struct ip_mreqn *imr); extern void ip_mc_drop_socket(struct sock *sk); extern int ip_mc_source(int add, int omode, struct sock *sk, struct ip_mreq_source *mreqs, int ifindex); extern int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf,int ifindex); extern int ip_mc_msfget(struct sock *sk, struct ip_msfilter *msf, sockptr_t optval, sockptr_t optlen); extern int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf, sockptr_t optval, size_t offset); extern int ip_mc_sf_allow(const struct sock *sk, __be32 local, __be32 rmt, int dif, int sdif); extern void ip_mc_init_dev(struct in_device *); extern void ip_mc_destroy_dev(struct in_device *); extern void ip_mc_up(struct in_device *); extern void ip_mc_down(struct in_device *); extern void ip_mc_unmap(struct in_device *); extern void ip_mc_remap(struct in_device *); extern void __ip_mc_dec_group(struct in_device *in_dev, __be32 addr, gfp_t gfp); static inline void ip_mc_dec_group(struct in_device *in_dev, __be32 addr) { return __ip_mc_dec_group(in_dev, addr, GFP_KERNEL); } extern void __ip_mc_inc_group(struct in_device *in_dev, __be32 addr, gfp_t gfp); extern void ip_mc_inc_group(struct in_device *in_dev, __be32 addr); int ip_mc_check_igmp(struct sk_buff *skb); #endif