net-caif: add CAIF generic caif support functions

Support functions for the caif protocol stack:
cfcnfg.c        - CAIF Configuration Module used for
                  adding and removing drivers and connection
cfpkt_skbuff.c  - CAIF Packet layer (SKB helper functions)

Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 571 insertions, 0 deletions

diff --git a/net/caif/cfpkt_skbuff.c b/net/caif/cfpkt_skbuff.c
new file mode 100644
index 0000000..83fff2f
--- /dev/null
+++ b/net/caif/cfpkt_skbuff.c
@@ -0,0 +1,571 @@
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Author:	Sjur Brendeland/sjur.brandeland@stericsson.com
+ * License terms: GNU General Public License (GPL) version 2
+ */
+
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <linux/hardirq.h>
+#include <net/caif/cfpkt.h>
+
+#define PKT_PREFIX CAIF_NEEDED_HEADROOM
+#define PKT_POSTFIX CAIF_NEEDED_TAILROOM
+#define PKT_LEN_WHEN_EXTENDING 128
+#define PKT_ERROR(pkt, errmsg) do {	   \
+    cfpkt_priv(pkt)->erronous = true;	   \
+    skb_reset_tail_pointer(&pkt->skb);	   \
+    pr_warning("CAIF: " errmsg);\
+  } while (0)
+
+struct cfpktq {
+	struct sk_buff_head head;
+	atomic_t count;
+	/* Lock protects count updates */
+	spinlock_t lock;
+};
+
+/*
+ * net/caif/ is generic and does not
+ * understand SKB, so we do this typecast
+ */
+struct cfpkt {
+	struct sk_buff skb;
+};
+
+/* Private data inside SKB */
+struct cfpkt_priv_data {
+	struct dev_info dev_info;
+	bool erronous;
+};
+
+inline struct cfpkt_priv_data *cfpkt_priv(struct cfpkt *pkt)
+{
+	return (struct cfpkt_priv_data *) pkt->skb.cb;
+}
+
+inline bool is_erronous(struct cfpkt *pkt)
+{
+	return cfpkt_priv(pkt)->erronous;
+}
+
+inline struct sk_buff *pkt_to_skb(struct cfpkt *pkt)
+{
+	return &pkt->skb;
+}
+
+inline struct cfpkt *skb_to_pkt(struct sk_buff *skb)
+{
+	return (struct cfpkt *) skb;
+}
+
+
+struct cfpkt *cfpkt_fromnative(enum caif_direction dir, void *nativepkt)
+{
+	struct cfpkt *pkt = skb_to_pkt(nativepkt);
+	cfpkt_priv(pkt)->erronous = false;
+	return pkt;
+}
+EXPORT_SYMBOL(cfpkt_fromnative);
+
+void *cfpkt_tonative(struct cfpkt *pkt)
+{
+	return (void *) pkt;
+}
+EXPORT_SYMBOL(cfpkt_tonative);
+
+static struct cfpkt *cfpkt_create_pfx(u16 len, u16 pfx)
+{
+	struct sk_buff *skb;
+
+	if (likely(in_interrupt()))
+		skb = alloc_skb(len + pfx, GFP_ATOMIC);
+	else
+		skb = alloc_skb(len + pfx, GFP_KERNEL);
+
+	if (unlikely(skb == NULL))
+		return NULL;
+
+	skb_reserve(skb, pfx);
+	return skb_to_pkt(skb);
+}
+
+inline struct cfpkt *cfpkt_create(u16 len)
+{
+	return cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
+}
+EXPORT_SYMBOL(cfpkt_create);
+
+void cfpkt_destroy(struct cfpkt *pkt)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	kfree_skb(skb);
+}
+EXPORT_SYMBOL(cfpkt_destroy);
+
+inline bool cfpkt_more(struct cfpkt *pkt)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	return skb->len > 0;
+}
+EXPORT_SYMBOL(cfpkt_more);
+
+int cfpkt_peek_head(struct cfpkt *pkt, void *data, u16 len)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	if (skb_headlen(skb) >= len) {
+		memcpy(data, skb->data, len);
+		return 0;
+	}
+	return !cfpkt_extr_head(pkt, data, len) &&
+	    !cfpkt_add_head(pkt, data, len);
+}
+EXPORT_SYMBOL(cfpkt_peek_head);
+
+int cfpkt_extr_head(struct cfpkt *pkt, void *data, u16 len)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	u8 *from;
+	if (unlikely(is_erronous(pkt)))
+		return -EPROTO;
+
+	if (unlikely(len > skb->len)) {
+		PKT_ERROR(pkt, "cfpkt_extr_head read beyond end of packet\n");
+		return -EPROTO;
+	}
+
+	if (unlikely(len > skb_headlen(skb))) {
+		if (unlikely(skb_linearize(skb) != 0)) {
+			PKT_ERROR(pkt, "cfpkt_extr_head linearize failed\n");
+			return -EPROTO;
+		}
+	}
+	from = skb_pull(skb, len);
+	from -= len;
+	memcpy(data, from, len);
+	return 0;
+}
+EXPORT_SYMBOL(cfpkt_extr_head);
+
+int cfpkt_extr_trail(struct cfpkt *pkt, void *dta, u16 len)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	u8 *data = dta;
+	u8 *from;
+	if (unlikely(is_erronous(pkt)))
+		return -EPROTO;
+
+	if (unlikely(skb_linearize(skb) != 0)) {
+		PKT_ERROR(pkt, "cfpkt_extr_trail linearize failed\n");
+		return -EPROTO;
+	}
+	if (unlikely(skb->data + len > skb_tail_pointer(skb))) {
+		PKT_ERROR(pkt, "cfpkt_extr_trail read beyond end of packet\n");
+		return -EPROTO;
+	}
+	from = skb_tail_pointer(skb) - len;
+	skb_trim(skb, skb->len - len);
+	memcpy(data, from, len);
+	return 0;
+}
+EXPORT_SYMBOL(cfpkt_extr_trail);
+
+int cfpkt_pad_trail(struct cfpkt *pkt, u16 len)
+{
+	return cfpkt_add_body(pkt, NULL, len);
+}
+EXPORT_SYMBOL(cfpkt_pad_trail);
+
+int cfpkt_add_body(struct cfpkt *pkt, const void *data, u16 len)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	struct sk_buff *lastskb;
+	u8 *to;
+	u16 addlen = 0;
+
+
+	if (unlikely(is_erronous(pkt)))
+		return -EPROTO;
+
+	lastskb = skb;
+
+	/* Check whether we need to add space at the tail */
+	if (unlikely(skb_tailroom(skb) < len)) {
+		if (likely(len < PKT_LEN_WHEN_EXTENDING))
+			addlen = PKT_LEN_WHEN_EXTENDING;
+		else
+			addlen = len;
+	}
+
+	/* Check whether we need to change the SKB before writing to the tail */
+	if (unlikely((addlen > 0) || skb_cloned(skb) || skb_shared(skb))) {
+
+		/* Make sure data is writable */
+		if (unlikely(skb_cow_data(skb, addlen, &lastskb) < 0)) {
+			PKT_ERROR(pkt, "cfpkt_add_body: cow failed\n");
+			return -EPROTO;
+		}
+		/*
+		 * Is the SKB non-linear after skb_cow_data()? If so, we are
+		 * going to add data to the last SKB, so we need to adjust
+		 * lengths of the top SKB.
+		 */
+		if (lastskb != skb) {
+			pr_warning("CAIF: %s(): Packet is non-linear\n",
+				   __func__);
+			skb->len += len;
+			skb->data_len += len;
+		}
+	}
+
+	/* All set to put the last SKB and optionally write data there. */
+	to = skb_put(lastskb, len);
+	if (likely(data))
+		memcpy(to, data, len);
+	return 0;
+}
+EXPORT_SYMBOL(cfpkt_add_body);
+
+inline int cfpkt_addbdy(struct cfpkt *pkt, u8 data)
+{
+	return cfpkt_add_body(pkt, &data, 1);
+}
+EXPORT_SYMBOL(cfpkt_addbdy);
+
+int cfpkt_add_head(struct cfpkt *pkt, const void *data2, u16 len)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	struct sk_buff *lastskb;
+	u8 *to;
+	const u8 *data = data2;
+	if (unlikely(is_erronous(pkt)))
+		return -EPROTO;
+	if (unlikely(skb_headroom(skb) < len)) {
+		PKT_ERROR(pkt, "cfpkt_add_head: no headroom\n");
+		return -EPROTO;
+	}
+
+	/* Make sure data is writable */
+	if (unlikely(skb_cow_data(skb, 0, &lastskb) < 0)) {
+		PKT_ERROR(pkt, "cfpkt_add_head: cow failed\n");
+		return -EPROTO;
+	}
+
+	to = skb_push(skb, len);
+	memcpy(to, data, len);
+	return 0;
+}
+EXPORT_SYMBOL(cfpkt_add_head);
+
+inline int cfpkt_add_trail(struct cfpkt *pkt, const void *data, u16 len)
+{
+	return cfpkt_add_body(pkt, data, len);
+}
+EXPORT_SYMBOL(cfpkt_add_trail);
+
+inline u16 cfpkt_getlen(struct cfpkt *pkt)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	return skb->len;
+}
+EXPORT_SYMBOL(cfpkt_getlen);
+
+inline u16 cfpkt_iterate(struct cfpkt *pkt,
+			    u16 (*iter_func)(u16, void *, u16),
+			    u16 data)
+{
+	/*
+	 * Don't care about the performance hit of linearizing,
+	 * Checksum should not be used on high-speed interfaces anyway.
+	 */
+	if (unlikely(is_erronous(pkt)))
+		return -EPROTO;
+	if (unlikely(skb_linearize(&pkt->skb) != 0)) {
+		PKT_ERROR(pkt, "cfpkt_iterate: linearize failed\n");
+		return -EPROTO;
+	}
+	return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt));
+}
+EXPORT_SYMBOL(cfpkt_iterate);
+
+int cfpkt_setlen(struct cfpkt *pkt, u16 len)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+
+
+	if (unlikely(is_erronous(pkt)))
+		return -EPROTO;
+
+	if (likely(len <= skb->len)) {
+		if (unlikely(skb->data_len))
+			___pskb_trim(skb, len);
+		else
+			skb_trim(skb, len);
+
+			return cfpkt_getlen(pkt);
+	}
+
+	/* Need to expand SKB */
+	if (unlikely(!cfpkt_pad_trail(pkt, len - skb->len)))
+		PKT_ERROR(pkt, "cfpkt_setlen: skb_pad_trail failed\n");
+
+	return cfpkt_getlen(pkt);
+}
+EXPORT_SYMBOL(cfpkt_setlen);
+
+struct cfpkt *cfpkt_create_uplink(const unsigned char *data, unsigned int len)
+{
+	struct cfpkt *pkt = cfpkt_create_pfx(len + PKT_POSTFIX, PKT_PREFIX);
+	if (unlikely(data != NULL))
+		cfpkt_add_body(pkt, data, len);
+	return pkt;
+}
+EXPORT_SYMBOL(cfpkt_create_uplink);
+
+struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
+			     struct cfpkt *addpkt,
+			     u16 expectlen)
+{
+	struct sk_buff *dst = pkt_to_skb(dstpkt);
+	struct sk_buff *add = pkt_to_skb(addpkt);
+	u16 addlen = skb_headlen(add);
+	u16 neededtailspace;
+	struct sk_buff *tmp;
+	u16 dstlen;
+	u16 createlen;
+	if (unlikely(is_erronous(dstpkt) || is_erronous(addpkt))) {
+		cfpkt_destroy(addpkt);
+		return dstpkt;
+	}
+	if (expectlen > addlen)
+		neededtailspace = expectlen;
+	else
+		neededtailspace = addlen;
+
+	if (dst->tail + neededtailspace > dst->end) {
+		/* Create a dumplicate of 'dst' with more tail space */
+		dstlen = skb_headlen(dst);
+		createlen = dstlen + neededtailspace;
+		tmp = pkt_to_skb(
+			cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX));
+		if (!tmp)
+			return NULL;
+		skb_set_tail_pointer(tmp, dstlen);
+		tmp->len = dstlen;
+		memcpy(tmp->data, dst->data, dstlen);
+		cfpkt_destroy(dstpkt);
+		dst = tmp;
+	}
+	memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add));
+	cfpkt_destroy(addpkt);
+	dst->tail += addlen;
+	dst->len += addlen;
+	return skb_to_pkt(dst);
+}
+EXPORT_SYMBOL(cfpkt_append);
+
+struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos)
+{
+	struct sk_buff *skb2;
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	u8 *split = skb->data + pos;
+	u16 len2nd = skb_tail_pointer(skb) - split;
+
+	if (unlikely(is_erronous(pkt)))
+		return NULL;
+
+	if (skb->data + pos > skb_tail_pointer(skb)) {
+		PKT_ERROR(pkt,
+			  "cfpkt_split: trying to split beyond end of packet");
+		return NULL;
+	}
+
+	/* Create a new packet for the second part of the data */
+	skb2 = pkt_to_skb(
+		cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX,
+				 PKT_PREFIX));
+
+	if (skb2 == NULL)
+		return NULL;
+
+	/* Reduce the length of the original packet */
+	skb_set_tail_pointer(skb, pos);
+	skb->len = pos;
+
+	memcpy(skb2->data, split, len2nd);
+	skb2->tail += len2nd;
+	skb2->len += len2nd;
+	return skb_to_pkt(skb2);
+}
+EXPORT_SYMBOL(cfpkt_split);
+
+char *cfpkt_log_pkt(struct cfpkt *pkt, char *buf, int buflen)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	char *p = buf;
+	int i;
+
+	/*
+	 * Sanity check buffer length, it needs to be at least as large as
+	 * the header info: ~=50+ bytes
+	 */
+	if (buflen < 50)
+		return NULL;
+
+	snprintf(buf, buflen, "%s: pkt:%p len:%ld(%ld+%ld) {%ld,%ld} data: [",
+		is_erronous(pkt) ? "ERRONOUS-SKB" :
+		 (skb->data_len != 0 ? "COMPLEX-SKB" : "SKB"),
+		 skb,
+		 (long) skb->len,
+		 (long) (skb_tail_pointer(skb) - skb->data),
+		 (long) skb->data_len,
+		 (long) (skb->data - skb->head),
+		 (long) (skb_tail_pointer(skb) - skb->head));
+	p = buf + strlen(buf);
+
+	for (i = 0; i < skb_tail_pointer(skb) - skb->data && i < 300; i++) {
+		if (p > buf + buflen - 10) {
+			sprintf(p, "...");
+			p = buf + strlen(buf);
+			break;
+		}
+		sprintf(p, "%02x,", skb->data[i]);
+		p = buf + strlen(buf);
+	}
+	sprintf(p, "]\n");
+	return buf;
+}
+EXPORT_SYMBOL(cfpkt_log_pkt);
+
+int cfpkt_raw_append(struct cfpkt *pkt, void **buf, unsigned int buflen)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	struct sk_buff *lastskb;
+
+	caif_assert(buf != NULL);
+	if (unlikely(is_erronous(pkt)))
+		return -EPROTO;
+	/* Make sure SKB is writable */
+	if (unlikely(skb_cow_data(skb, 0, &lastskb) < 0)) {
+		PKT_ERROR(pkt, "cfpkt_raw_append: skb_cow_data failed\n");
+		return -EPROTO;
+	}
+
+	if (unlikely(skb_linearize(skb) != 0)) {
+		PKT_ERROR(pkt, "cfpkt_raw_append: linearize failed\n");
+		return -EPROTO;
+	}
+
+	if (unlikely(skb_tailroom(skb) < buflen)) {
+		PKT_ERROR(pkt, "cfpkt_raw_append: buffer too short - failed\n");
+		return -EPROTO;
+	}
+
+	*buf = skb_put(skb, buflen);
+	return 1;
+}
+EXPORT_SYMBOL(cfpkt_raw_append);
+
+int cfpkt_raw_extract(struct cfpkt *pkt, void **buf, unsigned int buflen)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+
+	caif_assert(buf != NULL);
+	if (unlikely(is_erronous(pkt)))
+		return -EPROTO;
+
+	if (unlikely(buflen > skb->len)) {
+		PKT_ERROR(pkt, "cfpkt_raw_extract: buflen too large "
+				"- failed\n");
+		return -EPROTO;
+	}
+
+	if (unlikely(buflen > skb_headlen(skb))) {
+		if (unlikely(skb_linearize(skb) != 0)) {
+			PKT_ERROR(pkt, "cfpkt_raw_extract: linearize failed\n");
+			return -EPROTO;
+		}
+	}
+
+	*buf = skb->data;
+	skb_pull(skb, buflen);
+
+	return 1;
+}
+EXPORT_SYMBOL(cfpkt_raw_extract);
+
+inline bool cfpkt_erroneous(struct cfpkt *pkt)
+{
+	return cfpkt_priv(pkt)->erronous;
+}
+EXPORT_SYMBOL(cfpkt_erroneous);
+
+struct cfpktq *cfpktq_create(void)
+{
+	struct cfpktq *q = kmalloc(sizeof(struct cfpktq), GFP_ATOMIC);
+	if (!q)
+		return NULL;
+	skb_queue_head_init(&q->head);
+	atomic_set(&q->count, 0);
+	spin_lock_init(&q->lock);
+	return q;
+}
+EXPORT_SYMBOL(cfpktq_create);
+
+void cfpkt_queue(struct cfpktq *pktq, struct cfpkt *pkt, unsigned short prio)
+{
+	atomic_inc(&pktq->count);
+	spin_lock(&pktq->lock);
+	skb_queue_tail(&pktq->head, pkt_to_skb(pkt));
+	spin_unlock(&pktq->lock);
+
+}
+EXPORT_SYMBOL(cfpkt_queue);
+
+struct cfpkt *cfpkt_qpeek(struct cfpktq *pktq)
+{
+	struct cfpkt *tmp;
+	spin_lock(&pktq->lock);
+	tmp = skb_to_pkt(skb_peek(&pktq->head));
+	spin_unlock(&pktq->lock);
+	return tmp;
+}
+EXPORT_SYMBOL(cfpkt_qpeek);
+
+struct cfpkt *cfpkt_dequeue(struct cfpktq *pktq)
+{
+	struct cfpkt *pkt;
+	spin_lock(&pktq->lock);
+	pkt = skb_to_pkt(skb_dequeue(&pktq->head));
+	if (pkt) {
+		atomic_dec(&pktq->count);
+		caif_assert(atomic_read(&pktq->count) >= 0);
+	}
+	spin_unlock(&pktq->lock);
+	return pkt;
+}
+EXPORT_SYMBOL(cfpkt_dequeue);
+
+int cfpkt_qcount(struct cfpktq *pktq)
+{
+	return atomic_read(&pktq->count);
+}
+EXPORT_SYMBOL(cfpkt_qcount);
+
+struct cfpkt *cfpkt_clone_release(struct cfpkt *pkt)
+{
+	struct cfpkt *clone;
+	clone  = skb_to_pkt(skb_clone(pkt_to_skb(pkt), GFP_ATOMIC));
+	/* Free original packet. */
+	cfpkt_destroy(pkt);
+	if (!clone)
+		return NULL;
+	return clone;
+}
+EXPORT_SYMBOL(cfpkt_clone_release);
+
+struct caif_payload_info *cfpkt_info(struct cfpkt *pkt)
+{
+	return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb;
+}
+EXPORT_SYMBOL(cfpkt_info);