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Remove now unused IPv6 macros and update docs.

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After r354748-354750 all uses of the IP6_EXTHDR_CHECK() and
IP6_EXTHDR_GET() macros are gone from the kernel.  IP6_EXTHDR_GET0()
was unused.  Remove the macros and update the documentation.

Sponsored by:	Netflix
This commit is contained in:
Bjoern A. Zeeb 2019-11-15 21:55:41 +00:00
parent 4e619b17c5
commit b141dd5ddf
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=354751
2 changed files with 0 additions and 98 deletions
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14
share/doc/IPv6/IMPLEMENTATION
View File

@ -1049,20 +1049,6 @@ requirement. (For more information, refer to Section 2.)
3282 one ext mbuf
0 two or more ext mbuf
Each input function calls IP6_EXTHDR_CHECK in the beginning to check
if the region between IP6 and its header is
continuous. IP6_EXTHDR_CHECK calls m_pullup() only if the mbuf has
M_LOOP flag, that is, the packet comes from the loopback
interface. m_pullup() is never called for packets coming from physical
network interfaces.
TCP6 reassembly makes use of IP6 header to store reassemble
information. IP6 is not supposed to be just before TCP6, so
ip6tcpreass structure has a pointer to TCP6 header. Of course, it has
also a pointer back to mbuf to avoid m_pullup().
Like TCP6, both IP and IP6 reassemble functions never call m_pullup().
xxx_ctlinput() calls in_mrejoin() on PRC_IFNEWADDR. We think this is
one of 4.4BSD implementation flaws. Since 4.4BSD keeps ia_multiaddrs
in in_ifaddr{}, it can't use multicast feature if the interface has no

84
sys/netinet/ip6.h
View File

@ -262,88 +262,4 @@ struct ip6_frag {
#define IPV6_MAXPACKET 65535 /* ip6 max packet size without Jumbo payload*/
#define IPV6_MAXOPTHDR 2048 /* max option header size, 256 64-bit words */
#ifdef _KERNEL
/*
* IP6_EXTHDR_CHECK ensures that region between the IP6 header and the
* target header (including IPv6 itself, extension headers and
* TCP/UDP/ICMP6 headers) are contiguous. KAME requires drivers
* to store incoming data into one internal mbuf or one or more external
* mbufs(never into two or more internal mbufs). Thus, the third case is
* supposed to never be matched but is prepared just in case.
*/
#define IP6_EXTHDR_CHECK(m, off, hlen, ret) \
do { \
if ((m)->m_next != NULL) { \
if (((m)->m_flags & M_LOOP) && \
((m)->m_len < (off) + (hlen)) && \
(((m) = m_pullup((m), (off) + (hlen))) == NULL)) { \
IP6STAT_INC(ip6s_exthdrtoolong); \
return ret; \
} else { \
if ((m)->m_len < (off) + (hlen)) { \
IP6STAT_INC(ip6s_exthdrtoolong); \
m_freem(m); \
return ret; \
} \
} \
} else { \
if ((m)->m_len < (off) + (hlen)) { \
IP6STAT_INC(ip6s_tooshort); \
in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated); \
m_freem(m); \
return ret; \
} \
} \
} while (/*CONSTCOND*/ 0)
/*
* IP6_EXTHDR_GET ensures that intermediate protocol header (from "off" to
* "len") is located in single mbuf, on contiguous memory region.
* The pointer to the region will be returned to pointer variable "val",
* with type "typ".
* IP6_EXTHDR_GET0 does the same, except that it aligns the structure at the
* very top of mbuf. GET0 is likely to make memory copy than GET.
*
* XXX we're now testing this, needs m_pulldown()
*/
#define IP6_EXTHDR_GET(val, typ, m, off, len) \
do { \
struct mbuf *t; \
int tmp; \
if ((m)->m_len >= (off) + (len)) \
(val) = (typ)(mtod((m), caddr_t) + (off)); \
else { \
t = m_pulldown((m), (off), (len), &tmp); \
if (t) { \
if (t->m_len < tmp + (len)) \
panic("m_pulldown malfunction"); \
(val) = (typ)(mtod(t, caddr_t) + tmp); \
} else { \
(val) = (typ)NULL; \
(m) = NULL; \
} \
} \
} while (/*CONSTCOND*/ 0)
#define IP6_EXTHDR_GET0(val, typ, m, off, len) \
do { \
struct mbuf *t; \
if ((off) == 0) \
(val) = (typ)mtod(m, caddr_t); \
else { \
t = m_pulldown((m), (off), (len), NULL); \
if (t) { \
if (t->m_len < (len)) \
panic("m_pulldown malfunction"); \
(val) = (typ)mtod(t, caddr_t); \
} else { \
(val) = (typ)NULL; \
(m) = NULL; \
} \
} \
} while (/*CONSTCOND*/ 0)
#endif /*_KERNEL*/
#endif /* not _NETINET_IP6_H_ */