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authorChristophe Ricard <christophe.ricard@gmail.com>2015-08-19 21:26:43 +0200
committerSamuel Ortiz <sameo@linux.intel.com>2015-08-20 22:00:11 +0200
commit29e76924cf087bc6a9114a9244828fd13ae959bb (patch)
tree495b6ebf26ac799865f781c859ece692cc496662
parent5a9e0ffc0f128ecdf7c770f76c268e4f9f3c9118 (diff)
downloadop-kernel-dev-29e76924cf087bc6a9114a9244828fd13ae959bb.zip
op-kernel-dev-29e76924cf087bc6a9114a9244828fd13ae959bb.tar.gz
nfc: netlink: Add capability to reply to vendor_cmd with data
A proprietary vendor command may send back useful data to the user application. For example, the field level applied on the NFC router antenna. Still based on net/wireless/nl80211.c implementation, add nfc_vendor_cmd_alloc_reply_skb and nfc_vendor_cmd_reply in order to send back over netlink data generated by a proprietary command. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
-rw-r--r--include/net/nfc/nfc.h41
-rw-r--r--net/nfc/netlink.c86
2 files changed, 125 insertions, 2 deletions
diff --git a/include/net/nfc/nfc.h b/include/net/nfc/nfc.h
index f9e58ae..30afc9a 100644
--- a/include/net/nfc/nfc.h
+++ b/include/net/nfc/nfc.h
@@ -203,6 +203,7 @@ struct nfc_dev {
int n_vendor_cmds;
struct nfc_ops *ops;
+ struct genl_info *cur_cmd_info;
};
#define to_nfc_dev(_dev) container_of(_dev, struct nfc_dev, dev)
@@ -318,4 +319,44 @@ static inline int nfc_set_vendor_cmds(struct nfc_dev *dev,
return 0;
}
+struct sk_buff *__nfc_alloc_vendor_cmd_reply_skb(struct nfc_dev *dev,
+ enum nfc_attrs attr,
+ u32 oui, u32 subcmd,
+ int approxlen);
+int nfc_vendor_cmd_reply(struct sk_buff *skb);
+
+/**
+ * nfc_vendor_cmd_alloc_reply_skb - allocate vendor command reply
+ * @dev: nfc device
+ * @oui: vendor oui
+ * @approxlen: an upper bound of the length of the data that will
+ * be put into the skb
+ *
+ * This function allocates and pre-fills an skb for a reply to
+ * a vendor command. Since it is intended for a reply, calling
+ * it outside of a vendor command's doit() operation is invalid.
+ *
+ * The returned skb is pre-filled with some identifying data in
+ * a way that any data that is put into the skb (with skb_put(),
+ * nla_put() or similar) will end up being within the
+ * %NFC_ATTR_VENDOR_DATA attribute, so all that needs to be done
+ * with the skb is adding data for the corresponding userspace tool
+ * which can then read that data out of the vendor data attribute.
+ * You must not modify the skb in any other way.
+ *
+ * When done, call nfc_vendor_cmd_reply() with the skb and return
+ * its error code as the result of the doit() operation.
+ *
+ * Return: An allocated and pre-filled skb. %NULL if any errors happen.
+ */
+static inline struct sk_buff *
+nfc_vendor_cmd_alloc_reply_skb(struct nfc_dev *dev,
+ u32 oui, u32 subcmd, int approxlen)
+{
+ return __nfc_alloc_vendor_cmd_reply_skb(dev,
+ NFC_ATTR_VENDOR_DATA,
+ oui,
+ subcmd, approxlen);
+}
+
#endif /* __NET_NFC_H */
diff --git a/net/nfc/netlink.c b/net/nfc/netlink.c
index 73d1ca7..853172c 100644
--- a/net/nfc/netlink.c
+++ b/net/nfc/netlink.c
@@ -63,6 +63,8 @@ static const struct nla_policy nfc_genl_policy[NFC_ATTR_MAX + 1] = {
[NFC_ATTR_FIRMWARE_NAME] = { .type = NLA_STRING,
.len = NFC_FIRMWARE_NAME_MAXSIZE },
[NFC_ATTR_SE_APDU] = { .type = NLA_BINARY },
+ [NFC_ATTR_VENDOR_DATA] = { .type = NLA_BINARY },
+
};
static const struct nla_policy nfc_sdp_genl_policy[NFC_SDP_ATTR_MAX + 1] = {
@@ -1503,7 +1505,7 @@ static int nfc_genl_vendor_cmd(struct sk_buff *skb,
u32 dev_idx, vid, subcmd;
u8 *data;
size_t data_len;
- int i;
+ int i, err;
if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
!info->attrs[NFC_ATTR_VENDOR_ID] ||
@@ -1534,12 +1536,92 @@ static int nfc_genl_vendor_cmd(struct sk_buff *skb,
if (cmd->vendor_id != vid || cmd->subcmd != subcmd)
continue;
- return cmd->doit(dev, data, data_len);
+ dev->cur_cmd_info = info;
+ err = cmd->doit(dev, data, data_len);
+ dev->cur_cmd_info = NULL;
+ return err;
}
return -EOPNOTSUPP;
}
+/* message building helper */
+static inline void *nfc_hdr_put(struct sk_buff *skb, u32 portid, u32 seq,
+ int flags, u8 cmd)
+{
+ /* since there is no private header just add the generic one */
+ return genlmsg_put(skb, portid, seq, &nfc_genl_family, flags, cmd);
+}
+
+static struct sk_buff *
+__nfc_alloc_vendor_cmd_skb(struct nfc_dev *dev, int approxlen,
+ u32 portid, u32 seq,
+ enum nfc_attrs attr,
+ u32 oui, u32 subcmd, gfp_t gfp)
+{
+ struct sk_buff *skb;
+ void *hdr;
+
+ skb = nlmsg_new(approxlen + 100, gfp);
+ if (!skb)
+ return NULL;
+
+ hdr = nfc_hdr_put(skb, portid, seq, 0, NFC_CMD_VENDOR);
+ if (!hdr) {
+ kfree_skb(skb);
+ return NULL;
+ }
+
+ if (nla_put_u32(skb, NFC_ATTR_DEVICE_INDEX, dev->idx))
+ goto nla_put_failure;
+ if (nla_put_u32(skb, NFC_ATTR_VENDOR_ID, oui))
+ goto nla_put_failure;
+ if (nla_put_u32(skb, NFC_ATTR_VENDOR_SUBCMD, subcmd))
+ goto nla_put_failure;
+
+ ((void **)skb->cb)[0] = dev;
+ ((void **)skb->cb)[1] = hdr;
+
+ return skb;
+
+nla_put_failure:
+ kfree_skb(skb);
+ return NULL;
+}
+
+struct sk_buff *__nfc_alloc_vendor_cmd_reply_skb(struct nfc_dev *dev,
+ enum nfc_attrs attr,
+ u32 oui, u32 subcmd,
+ int approxlen)
+{
+ if (WARN_ON(!dev->cur_cmd_info))
+ return NULL;
+
+ return __nfc_alloc_vendor_cmd_skb(dev, approxlen,
+ dev->cur_cmd_info->snd_portid,
+ dev->cur_cmd_info->snd_seq, attr,
+ oui, subcmd, GFP_KERNEL);
+}
+EXPORT_SYMBOL(__nfc_alloc_vendor_cmd_reply_skb);
+
+int nfc_vendor_cmd_reply(struct sk_buff *skb)
+{
+ struct nfc_dev *dev = ((void **)skb->cb)[0];
+ void *hdr = ((void **)skb->cb)[1];
+
+ /* clear CB data for netlink core to own from now on */
+ memset(skb->cb, 0, sizeof(skb->cb));
+
+ if (WARN_ON(!dev->cur_cmd_info)) {
+ kfree_skb(skb);
+ return -EINVAL;
+ }
+
+ genlmsg_end(skb, hdr);
+ return genlmsg_reply(skb, dev->cur_cmd_info);
+}
+EXPORT_SYMBOL(nfc_vendor_cmd_reply);
+
static const struct genl_ops nfc_genl_ops[] = {
{
.cmd = NFC_CMD_GET_DEVICE,
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