diff options
Diffstat (limited to 'include/net/sctp/sctp.h')
| -rw-r--r-- | include/net/sctp/sctp.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h index 28b996d63490..0b98e4683f10 100644 --- a/include/net/sctp/sctp.h +++ b/include/net/sctp/sctp.h @@ -607,6 +607,25 @@ static inline struct dst_entry *sctp_transport_dst_check(struct sctp_transport * return t->dst; } +/* Calculate max payload size given a MTU, or the total overhead if + * given MTU is zero + */ +static inline __u32 sctp_mtu_payload(const struct sctp_sock *sp, + __u32 mtu, __u32 extra) +{ + __u32 overhead = sizeof(struct sctphdr) + extra; + + if (sp) + overhead += sp->pf->af->net_header_len; + else + overhead += sizeof(struct ipv6hdr); + + if (WARN_ON_ONCE(mtu && mtu <= overhead)) + mtu = overhead; + + return mtu ? mtu - overhead : overhead; +} + static inline bool sctp_transport_pmtu_check(struct sctp_transport *t) { __u32 pmtu = max_t(size_t, SCTP_TRUNC4(dst_mtu(t->dst)), |