[PATCH v2 17/20] doc: Add IP provider documentation

[eugene.loh@oracle.com]

From: Eugene Loh <eugene.loh@oracle.com>

Signed-off-by: Eugene Loh <eugene.loh@oracle.com>
Reviewed-by: Alan Maguire <alan.maguire@oracle.com>
---
 doc/userguide/index.md                        |  10 +
 doc/userguide/reference/dtrace_providers.md   |   2 +
 .../reference/dtrace_providers_ip.md          | 173 ++++++++++++++++++
 3 files changed, 185 insertions(+)
 create mode 100644 doc/userguide/reference/dtrace_providers_ip.md

diff --git a/doc/userguide/index.md b/doc/userguide/index.md
index ef1489f5e..063881c6d 100644
--- a/doc/userguide/index.md
+++ b/doc/userguide/index.md
@@ -208,6 +208,16 @@
             -   [fileinfo\_t](reference/dtrace_providers_io.md#dt_ref_iofile_prov)
         -   [io Examples](reference/dtrace_providers_io.md#dt_ref_ioexamples_prov)
         -   [io Stability](reference/dtrace_providers_io.md#dt_ref_iostab_prov)
+    -   [IP Provider](reference/dtrace_providers_ip.md)
+        -   [ip Probes](reference/dtrace_providers_ip.md#dt_ref_ipprobes_prov)
+        -   [ip Probe Arguments](reference/dtrace_providers_ip.md#dt_ref_ipargs_prov)
+            -   [pktinfo\_t](reference/dtrace_providers_ip.md#dt_ref_ippkt_prov)
+            -   [csinfo\_t](reference/dtrace_providers_ip.md#dt_ref_ipcs_prov)
+            -   [ipinfo\_t](reference/dtrace_providers_ip.md#dt_ref_ipip_prov)
+            -   [ifinfo\_t](reference/dtrace_providers_ip.md#dt_ref_ipif_prov)
+            -   [ipv4info\_t](reference/dtrace_providers_ip.md#dt_ref_ipipv4_prov)
+            -   [ipv6info\_t](reference/dtrace_providers_ip.md#dt_ref_ipipv6_prov)
+        -   [ip Stability](reference/dtrace_providers_ip.md#dt_ref_ipstab_prov)
     -   [Lockstat Provider](reference/dtrace_providers_lockstat.md#dt_ref_lockstat_prov)
         -   [lockstat Probes](reference/dtrace_providers_lockstat.md#dt_ref_lockstatprobes_prov)
         -   [lockstat Probe Arguments](reference/dtrace_providers_lockstat.md#dt_ref_lockstatargs_prov)
diff --git a/doc/userguide/reference/dtrace_providers.md b/doc/userguide/reference/dtrace_providers.md
index 70fcb583f..a225f4486 100644
--- a/doc/userguide/reference/dtrace_providers.md
+++ b/doc/userguide/reference/dtrace_providers.md
@@ -11,6 +11,8 @@ The `dtrace` provider includes several probes that are specific to DTrace itself
 The `fbt` \(Function Boundary Tracing\) provider includes probes that are associated with the entry to and return from most functions in the Linux kernel. Therefore, there could be tens of thousands of `fbt` probes.
 -   **[IO Provider](../reference/dtrace_providers_io.md)**
 The `io` provider makes available probes that relate to data input and output.
+-   **[IP Provider](../reference/dtrace_providers_ip.md)**
+The `ip` provider provides probes that can be used to study IP traffic.
 -   **[Lockstat Provider](../reference/dtrace_providers_lockstat.md)**
 The `lockstat` provider provides probes that can be used to study lock usage and contention.
 -   **[Pid Provider](../reference/dtrace_providers_pid.md)**
diff --git a/doc/userguide/reference/dtrace_providers_ip.md b/doc/userguide/reference/dtrace_providers_ip.md
new file mode 100644
index 000000000..0630e577a
--- /dev/null
+++ b/doc/userguide/reference/dtrace_providers_ip.md
@@ -0,0 +1,173 @@
+# IP Provider
+
+The `ip` provider makes available a probe at IP send operations in the system and a probe at receive.
+
+**Parent topic:**[DTrace Provider Reference](../reference/dtrace_providers.md)
+
+## ip Probes <a id="dt_ref_ipprobes_prov">
+
+The `ip` provider provides one probe for IP sends and another for IP receives.
+The module name is always `vmlinux` and the function name is empty.
+
+## ip Probe Arguments <a id="dt_ref_ipargs_prov">
+
+The following table lists the argument types for both the `send` and `receive` probes.
+
+| arg       | type            |
+| :---      | :---            |
+| `args[0]` | `pktinfo_t *`   |
+| `args[1]` | `csinfo_t *`    |
+| `args[2]` | `ipinfo_t *`    |
+| `args[3]` | `ifinfo_t *`    |
+| `args[4]` | `ipv4info_t *`  |
+| `args[5]` | `ipv6sinfo_t *` |
+
+### pktinfo\_t <a id="dt_ref_ippkt_prov">
+
+The `pktinfo_t` structure is an abstraction that describes a packet.
+Detailed information about this data structure can be found in
+`/usr/lib64/dtrace/*version*/ip.d` or
+`/usr/lib64/dtrace/*version*/net.d`, depending on `dtrace` version.
+The definition of `pktinfo_t` is as follows:
+
+```nocopybutton
+typedef struct pktinfo {
+        uintptr_t pkt_addr;
+} pktinfo_t;
+```
+
+**Note:**
+
+DTrace translates the members of `pktinfo_t` from the `struct sk_buff *`.
+
+### csinfo\_t <a id="dt_ref_ipcs_prov">
+
+The `csinfo_t` structure is an abstraction that describes connection state.
+Detailed information about this data structure can be found in
+`/usr/lib64/dtrace/*version*/ip.d` or
+`/usr/lib64/dtrace/*version*/net.d`, depending on `dtrace` version.
+The definition of `csinfo_t` is as follows:
+
+```nocopybutton
+typedef struct csinfo {
+	uintptr_t	cs_addr;
+	uint64_t	cs_cid;
+} csinfo_t;
+```
+
+**Note:**
+
+DTrace translates the members of `csinfo_t` from the `struct sock *`.
+
+### ipinfo\_t <a id="dt_ref_ipip_prov">
+
+The `ipinfo_t` structure contains common IP info for both IPv4 and IPv6.
+Detailed information about this data structure can be found in `/usr/lib64/dtrace/*version*/ip.d`.
+The definition of `ipinfo_t` is as follows:
+
+```nocopybutton
+typedef struct ipinfo {
+        uint8_t ip_ver;         /* IP version (4, 6) */
+        uint32_t ip_plength;    /* payload length */
+        string ip_saddr;        /* source address */
+        string ip_daddr;        /* destination address */
+} ipinfo_t;
+```
+
+**Note:**
+
+DTrace translates the members of `ipinfo_t` from, variously,
+`struct iphdr *`, `struct ipv6hdr *`, or `void_ip_t *`.
+
+### ifinfo\_t <a id="dt_ref_ipif_prov">
+
+The `ifinfo_t` structure contains network interface info.
+Detailed information about this data structure can be found in `/usr/lib64/dtrace/*version*/ip.d`.
+The definition of `ifinfo_t` is as follows:
+
+```nocopybutton
+typedef struct ifinfo {
+        string if_name;            /* interface name */
+        int8_t if_local;           /* is delivered locally */
+        netstackid_t if_ipstack;   /* netns pointer on Linux */
+        uintptr_t if_addr;         /* pointer to raw struct net_device */
+} ifinfo_t;
+```
+
+**Note:**
+
+DTrace translates the members of `ifinfo_t` from a `struct net_device *`.
+
+### ipv4info\_t <a id="dt_ref_ipipv4_prov">
+
+The `ipv4info_t` structure is translated version of the IPv4 header
+(with raw pointer).
+These values are NULL if the packet is not IPv4.
+Detailed information about this data structure can be found in `/usr/lib64/dtrace/*version*/ip.d`.
+The definition of `ipv4info_t` is as follows:
+
+```nocopybutton
+typedef struct ipv4info {
+        uint8_t ipv4_ver;               /* IP version (4) */
+        uint8_t ipv4_ihl;               /* header length, bytes */
+        uint8_t ipv4_tos;               /* type of service field */
+        uint16_t ipv4_length;           /* length (header + payload) */
+        uint16_t ipv4_ident;            /* identification */
+        uint8_t ipv4_flags;             /* IP flags */
+        uint16_t ipv4_offset;           /* fragment offset */
+        uint8_t ipv4_ttl;               /* time to live */
+        uint8_t ipv4_protocol;          /* next level protocol */
+        string ipv4_protostr;           /* next level protocol, as string */
+        uint16_t ipv4_checksum;         /* header checksum */
+        ipaddr_t ipv4_src;              /* source address */
+        ipaddr_t ipv4_dst;              /* destination address */
+        string ipv4_saddr;              /* source address, string */
+        string ipv4_daddr;              /* destination address, string */
+        struct iphdr *ipv4_hdr;         /* pointer to raw header */
+} ipv4info_t;
+```
+
+**Note:**
+
+DTrace translates the members of `ipv4info_t` from a `struct iphdr *`.
+
+### ipv6info\_t <a id="dt_ref_ipipv6_prov">
+
+The `ipv6info_t` structure is translated version of the IPv6 header
+(with raw pointer).
+These values are NULL if the packet is not IPv6.
+Detailed information about this data structure can be found in `/usr/lib64/dtrace/*version*/ip.d`.
+The definition of `ipv6info_t` is as follows:
+
+```nocopybutton
+typedef struct ipv6info {
+        uint8_t ipv6_ver;               /* IP version (6) */
+        uint8_t ipv6_tclass;            /* traffic class */
+        uint32_t ipv6_flow;             /* flow label */
+        uint16_t ipv6_plen;             /* payload length */
+        uint8_t ipv6_nexthdr;           /* next header protocol */
+        string ipv6_nextstr;            /* next header protocol, as string */
+        uint8_t ipv6_hlim;              /* hop limit */
+        in6_addr_t *ipv6_src;           /* source address */
+        in6_addr_t *ipv6_dst;           /* destination address */
+        string ipv6_saddr;              /* source address, string */
+        string ipv6_daddr;              /* destination address, string */
+        struct ipv6hdr *ipv6_hdr;       /* pointer to raw header */
+} ipv6info_t;
+```
+
+**Note:**
+
+DTrace translates the members of `ipv6info_t` from a `struct ipv6hdr *`.
+
+## ip Stability <a id="dt_ref_ipstab_prov">
+
+The `ip` provider uses DTrace's stability mechanism to describe its stabilities. These stability values are listed in the following table.
+
+| Element   | Name Stability | Data Stability | Dependency Class |
+| :---      | :---           | :---           | :---             |
+| Provider  | Evolving       | Evolving       | ISA              |
+| Module    | Private        | Private        | Unknown          |
+| Function  | Private        | Private        | Unknown          |
+| Name      | Evolving       | Evolving       | ISA              |
+| Arguments | Evolving       | Evolving       | ISA              |
-- 
2.47.3