uipc_mbuf2.c

来自「eCos操作系统源码」· C语言 代码 · 共 686 行 · 第 1/2 页

ok:
#ifdef PULLDOWN_DEBUG
    {
	struct mbuf *t;
	printf("after:");
	for (t = m; t; t = t->m_next)
		printf("%c%d", t == n ? '*' : ' ', t->m_len);
	printf(" (off=%d)\n", off);
    }
#endif
	if (offp)
		*offp = off;
	return n;
}

#ifndef __NetBSD__
static struct mbuf *
m_dup1(m, off, len, wait)
	struct mbuf *m;
	int off;
	int len;
	int wait;
{
	struct mbuf *n;
	int l;
	int copyhdr;

	if (len > MCLBYTES)
		return NULL;
	if (off == 0 && (m->m_flags & M_PKTHDR) != 0) {
		copyhdr = 1;
		MGETHDR(n, wait, m->m_type);
		l = MHLEN;
	} else {
		copyhdr = 0;
		MGET(n, wait, m->m_type);
		l = MLEN;
	}
	if (n && len > l) {
		MCLGET(n, wait);
		if ((n->m_flags & M_EXT) == 0) {
			m_free(n);
			n = NULL;
		}
	}
	if (!n)
		return NULL;

	if (copyhdr) {
#ifdef __OpenBSD__
		M_MOVE_PKTHDR(n, m);
#else
		M_COPY_PKTHDR(n, m);
#endif
	}
	m_copydata(m, off, len, mtod(n, caddr_t));
	n->m_len = len;

	return n;
}
#endif

/*
 * pkthdr.aux chain manipulation.
 * we don't allow clusters at this moment. 
 */
struct mbuf *
m_aux_add2(m, af, type, p)
	struct mbuf *m;
	int af, type;
	void *p;
{
	struct mbuf *n;
	struct mauxtag *t;

	if ((m->m_flags & M_PKTHDR) == 0)
		return NULL;

	n = m_aux_find(m, af, type);
	if (n)
		return n;

	MGET(n, M_DONTWAIT, m->m_type);
	if (n == NULL)
		return NULL;

	t = mtod(n, struct mauxtag *);
	bzero(t, sizeof(*t));
	t->af = af;
	t->type = type;
	t->p = p;
	n->m_data += sizeof(struct mauxtag);
	n->m_len = 0;
	n->m_next = m->m_pkthdr.aux;
	m->m_pkthdr.aux = n;
	return n;
}

struct mbuf *
m_aux_find2(m, af, type, p)
	struct mbuf *m;
	int af, type;
	void *p;
{
	struct mbuf *n;
	struct mauxtag *t;

	if ((m->m_flags & M_PKTHDR) == 0)
		return NULL;

	for (n = m->m_pkthdr.aux; n; n = n->m_next) {
		t = (struct mauxtag *)n->m_dat;
		if (n->m_data != ((caddr_t)t) + sizeof(struct mauxtag)) {
			printf("m_aux_find: invalid m_data for mbuf=%p (%p %p)\n", n, t, n->m_data);
			continue;
		}
		if (t->af == af && t->type == type && t->p == p)
			return n;
	}
	return NULL;
}

struct mbuf *
m_aux_find(m, af, type)
	struct mbuf *m;
	int af, type;
{

	return m_aux_find2(m, af, type, NULL);
}

struct mbuf *
m_aux_add(m, af, type)
	struct mbuf *m;
	int af, type;
{

	return m_aux_add2(m, af, type, NULL);
}

void
m_aux_delete(m, victim)
	struct mbuf *m;
	struct mbuf *victim;
{
	struct mbuf *n, *prev, *next;
	struct mauxtag *t;

	if ((m->m_flags & M_PKTHDR) == 0)
		return;

	prev = NULL;
	n = m->m_pkthdr.aux;
	while (n) {
		t = (struct mauxtag *)n->m_dat;
		next = n->m_next;
		if (n->m_data != ((caddr_t)t) + sizeof(struct mauxtag)) {
			printf("m_aux_delete: invalid m_data for mbuf=%p (%p %p)\n", n, t, n->m_data);
			prev = n;
			n = next;
			continue;
		}
		if (n == victim) {
			if (prev)
				prev->m_next = n->m_next;
			else
				m->m_pkthdr.aux = n->m_next;
			n->m_next = NULL;
			m_free(n);
		} else
			prev = n;
		n = next;
	}
}

#ifdef __OpenBSD__
/* Get a packet tag structure along with specified data following. */
struct m_tag *
m_tag_get(type, len, wait)
	int type;
	int len;
	int wait;
{
	struct m_tag *t;

	if (len < 0)
		return (NULL);
	MALLOC(t, struct m_tag *, len + sizeof(struct m_tag), M_PACKET_TAGS,
	    wait);
	if (t == NULL)
		return (NULL);
	t->m_tag_id = type;
	t->m_tag_len = len;
	return (t);
}

/* Free a packet tag. */
void
m_tag_free(t)
	struct m_tag *t;
{
	FREE(t, M_PACKET_TAGS);
}

/* Prepend a packet tag. */
void
m_tag_prepend(m, t)
	struct mbuf *m;
	struct m_tag *t;
{
	SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
}

/* Unlink a packet tag. */
void
m_tag_unlink(m, t)
	struct mbuf *m;
	struct m_tag *t;
{
	SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
}

/* Unlink and free a packet tag. */
void
m_tag_delete(m, t)
	struct mbuf *m;
	struct m_tag *t;
{
	m_tag_unlink(m, t);
	m_tag_free(t);
}

/* Unlink and free a packet tag chain, starting from given tag. */
void
m_tag_delete_chain(m, t)
	struct mbuf *m;
	struct m_tag *t;
{
	struct m_tag *p, *q;

	if (t != NULL)
		p = t;
	else
		p = SLIST_FIRST(&m->m_pkthdr.tags);
	if (p == NULL)
		return;
	while ((q = SLIST_NEXT(p, m_tag_link)) != NULL)
		m_tag_delete(m, q);
	m_tag_delete(m, p);
}

/* Find a tag, starting from a given position. */
struct m_tag *
m_tag_find(m, type, t)
	struct mbuf *m;
	int type;
	struct m_tag *t;
{
	struct m_tag *p;

	if (t == NULL)
		p = SLIST_FIRST(&m->m_pkthdr.tags);
	else
		p = SLIST_NEXT(t, m_tag_link);
	while (p != NULL) {
		if (p->m_tag_id == type)
			return (p);
		p = SLIST_NEXT(p, m_tag_link);
	}
	return (NULL);
}

/* Copy a single tag. */
struct m_tag *
m_tag_copy(t)
	struct m_tag *t;
{
	struct m_tag *p;

	p = m_tag_get(t->m_tag_id, t->m_tag_len, M_NOWAIT);
	if (p == NULL)
		return (NULL);
	bcopy(t + 1, p + 1, t->m_tag_len); /* Copy the data */
	return (p);
}

/*
 * Copy two tag chains. The destination mbuf (to) loses any attached
 * tags even if the operation fails. This should not be a problem, as
 * m_tag_copy_chain() is typically called with a newly-allocated
 * destination mbuf.
 */
int
m_tag_copy_chain(to, from)
	struct mbuf *to;
	struct mbuf *from;
{
	struct m_tag *p, *t, *tprev = NULL;

	m_tag_delete_chain(to, NULL);
	SLIST_FOREACH(p, &from->m_pkthdr.tags, m_tag_link) {
		t = m_tag_copy(p);
		if (t == NULL) {
			m_tag_delete_chain(to, NULL);
			return (0);
		}
		if (tprev == NULL)
			SLIST_INSERT_HEAD(&to->m_pkthdr.tags, t, m_tag_link);
		else {
			SLIST_INSERT_AFTER(tprev, t, m_tag_link);
			tprev = t;
		}
	}
	return (1);
}

/* Initialize tags on an mbuf. */
void
m_tag_init(m)
	struct mbuf *m;
{
	SLIST_INIT(&m->m_pkthdr.tags);
}

/* Get first tag in chain. */
struct m_tag *
m_tag_first(m)
	struct mbuf *m;
{
	return (SLIST_FIRST(&m->m_pkthdr.tags));
}

/* Get next tag in chain. */
struct m_tag *
m_tag_next(m, t)
	struct mbuf *m;
	struct m_tag *t;
{
	return (SLIST_NEXT(t, m_tag_link));
}
#endif /* OpenBSD */