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 000000000000..83fff2ff6658
--- /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);