diff options
Diffstat (limited to 'sys/netinet/ip_ecn.c')
-rw-r--r-- | sys/netinet/ip_ecn.c | 84 |
1 files changed, 71 insertions, 13 deletions
diff --git a/sys/netinet/ip_ecn.c b/sys/netinet/ip_ecn.c index de3d38e..9ea2f6b 100644 --- a/sys/netinet/ip_ecn.c +++ b/sys/netinet/ip_ecn.c @@ -1,5 +1,5 @@ /* $FreeBSD$ */ -/* $KAME: ip_ecn.c,v 1.11 2001/05/03 16:09:29 itojun Exp $ */ +/* $KAME: ip_ecn.c,v 1.12 2002/01/07 11:34:47 kjc Exp $ */ /* * Copyright (C) 1999 WIDE Project. @@ -56,6 +56,37 @@ #endif /* + * ECN and TOS (or TCLASS) processing rules at tunnel encapsulation and + * decapsulation from RFC3168: + * + * Outer Hdr at Inner Hdr at + * Encapsulator Decapsulator + * Header fields: -------------------- ------------ + * DS Field copied from inner hdr no change + * ECN Field constructed by (I) constructed by (E) + * + * ECN_ALLOWED (full functionality): + * (I) if the ECN field in the inner header is set to CE, then set the + * ECN field in the outer header to ECT(0). + * otherwise, copy the ECN field to the outer header. + * + * (E) if the ECN field in the outer header is set to CE and the ECN + * field of the inner header is not-ECT, drop the packet. + * if the ECN field in the inner header is set to ECT(0) or ECT(1) + * and the ECN field in the outer header is set to CE, then copy CE to + * the inner header. otherwise, make no change to the inner header. + * + * ECN_FORBIDDEN (limited functionality): + * (I) set the ECN field to not-ECT in the outer header. + * + * (E) if the ECN field in the outer header is set to CE, drop the packet. + * otherwise, make no change to the ECN field in the inner header. + * + * the drop rule is for backward compatibility and protection against + * erasure of CE. + */ + +/* * modify outer ECN (TOS) field on ingress operation (tunnel encapsulation). */ void @@ -70,10 +101,18 @@ ip_ecn_ingress(mode, outer, inner) *outer = *inner; switch (mode) { case ECN_ALLOWED: /* ECN allowed */ - *outer &= ~IPTOS_CE; + /* + * full-functionality: if the inner is CE, set ECT(0) + * to the outer. otherwise, copy the ECN field. + */ + if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_CE) + *outer &= ~IPTOS_ECN_ECT1; break; case ECN_FORBIDDEN: /* ECN forbidden */ - *outer &= ~(IPTOS_ECT | IPTOS_CE); + /* + * limited-functionality: set not-ECT to the outer + */ + *outer &= ~IPTOS_ECN_MASK; break; case ECN_NOCARE: /* no consideration to ECN */ break; @@ -82,8 +121,9 @@ ip_ecn_ingress(mode, outer, inner) /* * modify inner ECN (TOS) field on egress operation (tunnel decapsulation). + * the caller should drop the packet if the return value is 0. */ -void +int ip_ecn_egress(mode, outer, inner) int mode; const u_int8_t *outer; @@ -94,13 +134,28 @@ ip_ecn_egress(mode, outer, inner) switch (mode) { case ECN_ALLOWED: - if (*outer & IPTOS_CE) - *inner |= IPTOS_CE; + /* + * full-functionality: if the outer is CE and the inner is + * not-ECT, should drop it. otherwise, copy CE. + */ + if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE) { + if ((*inner & IPTOS_ECN_MASK) == IPTOS_ECN_NOTECT) + return (0); + *inner |= IPTOS_ECN_CE; + } break; case ECN_FORBIDDEN: /* ECN forbidden */ + /* + * limited-functionality: if the outer is CE, should drop it. + * otherwise, leave the inner. + */ + if ((*outer & IPTOS_ECN_MASK) == IPTOS_ECN_CE) + return (0); + break; case ECN_NOCARE: /* no consideration to ECN */ break; } + return (1); } #ifdef INET6 @@ -115,28 +170,31 @@ ip6_ecn_ingress(mode, outer, inner) if (!outer || !inner) panic("NULL pointer passed to ip6_ecn_ingress"); - outer8 = (ntohl(*outer) >> 20) & 0xff; inner8 = (ntohl(*inner) >> 20) & 0xff; ip_ecn_ingress(mode, &outer8, &inner8); *outer &= ~htonl(0xff << 20); *outer |= htonl((u_int32_t)outer8 << 20); } -void +int ip6_ecn_egress(mode, outer, inner) int mode; const u_int32_t *outer; u_int32_t *inner; { - u_int8_t outer8, inner8; + u_int8_t outer8, inner8, oinner8; if (!outer || !inner) panic("NULL pointer passed to ip6_ecn_egress"); outer8 = (ntohl(*outer) >> 20) & 0xff; - inner8 = (ntohl(*inner) >> 20) & 0xff; - ip_ecn_egress(mode, &outer8, &inner8); - *inner &= ~htonl(0xff << 20); - *inner |= htonl((u_int32_t)inner8 << 20); + inner8 = oinner8 = (ntohl(*inner) >> 20) & 0xff; + if (ip_ecn_egress(mode, &outer8, &inner8) == 0) + return (0); + if (inner8 != oinner8) { + *inner &= ~htonl(0xff << 20); + *inner |= htonl((u_int32_t)inner8 << 20); + } + return (1); } #endif |