d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

add m_append utility function to be used in forthcoming changes

Browse Source
This commit is contained in:
Sam Leffler 2004-12-08 05:42:02 +00:00
parent 3518d22073
commit 4873d1754f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=138541
2 changed files with 47 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
sys/kern/uipc_mbuf.c
View File

@ -933,6 +933,52 @@ out: if (((m = m0)->m_flags & M_PKTHDR) && (m->m_pkthdr.len < totlen))
m->m_pkthdr.len = totlen;
}
/*
* Append the specified data to the indicated mbuf chain,
* Extend the mbuf chain if the new data does not fit in
* existing space.
*
* Return 1 if able to complete the job; otherwise 0.
*/
int
m_append(struct mbuf *m0, int len, c_caddr_t cp)
{
struct mbuf *m, *n;
int remainder, space;
for (m = m0; m->m_next != NULL; m = m->m_next)
;
remainder = len;
space = M_TRAILINGSPACE(m);
if (space > 0) {
/*
* Copy into available space.
*/
if (space > remainder)
space = remainder;
bcopy(cp, mtod(m, caddr_t) + m->m_len, space);
m->m_len += space;
cp += space, remainder -= space;
}
while (remainder > 0) {
/*
* Allocate a new mbuf; could check space
* and allocate a cluster instead.
*/
n = m_get(M_DONTWAIT, m->m_type);
if (n == NULL)
break;
n->m_len = min(MLEN, remainder);
bcopy(cp, mtod(m, caddr_t), m->m_len);
cp += m->m_len, remainder -= m->m_len;
m->m_next = n;
m = n;
}
if (m0->m_flags & M_PKTHDR)
m0->m_pkthdr.len += len - remainder;
return (remainder == 0);
}
/*
* Apply function f to the data in an mbuf chain starting "off" bytes from
* the beginning, continuing for "len" bytes.

1
sys/sys/mbuf.h
View File

@ -535,6 +535,7 @@ struct uio;
void m_adj(struct mbuf *, int);
int m_apply(struct mbuf *, int, int,
int (*)(void *, void *, u_int), void *);
int m_append(struct mbuf *, int, c_caddr_t);
void m_cat(struct mbuf *, struct mbuf *);
void m_extadd(struct mbuf *, caddr_t, u_int,
void (*)(void *, void *), void *, int, int);