1 files changed, 382 insertions, 0 deletions
diff --git a/net/caif/cfpkt_skbuff.c b/net/caif/cfpkt_skbuff.c
new file mode 100644
index 0000000000..7796414d47
--- /dev/null
+++ b/net/caif/cfpkt_skbuff.c
@@ -0,0 +1,382 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) ST-Ericsson AB 2010
+ * Author:	Sjur Brendeland
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
+
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <linux/export.h>
+#include <net/caif/cfpkt.h>
+
+#define PKT_PREFIX  48
+#define PKT_POSTFIX 2
+#define PKT_LEN_WHEN_EXTENDING 128
+#define PKT_ERROR(pkt, errmsg)		   \
+do {					   \
+	cfpkt_priv(pkt)->erronous = true;  \
+	skb_reset_tail_pointer(&pkt->skb); \
+	pr_warn(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;
+};
+
+static inline struct cfpkt_priv_data *cfpkt_priv(struct cfpkt *pkt)
+{
+	return (struct cfpkt_priv_data *) pkt->skb.cb;
+}
+
+static inline bool is_erronous(struct cfpkt *pkt)
+{
+	return cfpkt_priv(pkt)->erronous;
+}
+
+static inline struct sk_buff *pkt_to_skb(struct cfpkt *pkt)
+{
+	return &pkt->skb;
+}
+
+static 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;
+
+	skb = alloc_skb(len + pfx, GFP_ATOMIC);
+	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);
+}
+
+void cfpkt_destroy(struct cfpkt *pkt)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	kfree_skb(skb);
+}
+
+inline bool cfpkt_more(struct cfpkt *pkt)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	return skb->len > 0;
+}
+
+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);
+}
+
+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, "read beyond end of packet\n");
+		return -EPROTO;
+	}
+
+	if (unlikely(len > skb_headlen(skb))) {
+		if (unlikely(skb_linearize(skb) != 0)) {
+			PKT_ERROR(pkt, "linearize failed\n");
+			return -EPROTO;
+		}
+	}
+	from = skb_pull(skb, len);
+	from -= len;
+	if (data)
+		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, "linearize failed\n");
+		return -EPROTO;
+	}
+	if (unlikely(skb->data + len > skb_tail_pointer(skb))) {
+		PKT_ERROR(pkt, "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;
+}
+
+int cfpkt_pad_trail(struct cfpkt *pkt, u16 len)
+{
+	return cfpkt_add_body(pkt, NULL, len);
+}
+
+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, "cow failed\n");
+			return -EPROTO;
+		}
+	}
+
+	/* All set to put the last SKB and optionally write data there. */
+	to = pskb_put(skb, lastskb, len);
+	if (likely(data))
+		memcpy(to, data, len);
+	return 0;
+}
+
+inline int cfpkt_addbdy(struct cfpkt *pkt, u8 data)
+{
+	return cfpkt_add_body(pkt, &data, 1);
+}
+
+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;
+	int ret;
+	if (unlikely(is_erronous(pkt)))
+		return -EPROTO;
+	if (unlikely(skb_headroom(skb) < len)) {
+		PKT_ERROR(pkt, "no headroom\n");
+		return -EPROTO;
+	}
+
+	/* Make sure data is writable */
+	ret = skb_cow_data(skb, 0, &lastskb);
+	if (unlikely(ret < 0)) {
+		PKT_ERROR(pkt, "cow failed\n");
+		return ret;
+	}
+
+	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);
+}
+
+inline u16 cfpkt_getlen(struct cfpkt *pkt)
+{
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	return skb->len;
+}
+
+int 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, "linearize failed\n");
+		return -EPROTO;
+	}
+	return iter_func(data, pkt->skb.data, cfpkt_getlen(pkt));
+}
+
+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, "skb_pad_trail failed\n");
+
+	return cfpkt_getlen(pkt);
+}
+
+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))) {
+		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 */
+		struct cfpkt *tmppkt;
+		dstlen = skb_headlen(dst);
+		createlen = dstlen + neededtailspace;
+		tmppkt = cfpkt_create(createlen + PKT_PREFIX + PKT_POSTFIX);
+		if (tmppkt == NULL)
+			return NULL;
+		tmp = pkt_to_skb(tmppkt);
+		skb_put_data(tmp, dst->data, dstlen);
+		cfpkt_destroy(dstpkt);
+		dst = tmp;
+	}
+	skb_put_data(dst, add->data, skb_headlen(add));
+	cfpkt_destroy(addpkt);
+	return skb_to_pkt(dst);
+}
+
+struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos)
+{
+	struct sk_buff *skb2;
+	struct sk_buff *skb = pkt_to_skb(pkt);
+	struct cfpkt *tmppkt;
+	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, "trying to split beyond end of packet\n");
+		return NULL;
+	}
+
+	/* Create a new packet for the second part of the data */
+	tmppkt = cfpkt_create_pfx(len2nd + PKT_PREFIX + PKT_POSTFIX,
+				  PKT_PREFIX);
+	if (tmppkt == NULL)
+		return NULL;
+	skb2 = pkt_to_skb(tmppkt);
+
+
+	if (skb2 == NULL)
+		return NULL;
+
+	skb_put_data(skb2, split, len2nd);
+
+	/* Reduce the length of the original packet */
+	skb_trim(skb, pos);
+
+	skb2->priority = skb->priority;
+	return skb_to_pkt(skb2);
+}
+
+bool cfpkt_erroneous(struct cfpkt *pkt)
+{
+	return cfpkt_priv(pkt)->erronous;
+}
+
+struct caif_payload_info *cfpkt_info(struct cfpkt *pkt)
+{
+	return (struct caif_payload_info *)&pkt_to_skb(pkt)->cb;
+}
+EXPORT_SYMBOL(cfpkt_info);
+
+void cfpkt_set_prio(struct cfpkt *pkt, int prio)
+{
+	pkt_to_skb(pkt)->priority = prio;
+}
+EXPORT_SYMBOL(cfpkt_set_prio);