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// Copyright 2024 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
package declextract
import (
"fmt"
"strings"
)
func (ctx *context) serializeNetlink() {
// policyQueue helps to emit policies on their first use.
pq := &policyQueue{
policies: make(map[string]*NetlinkPolicy),
}
for _, pol := range ctx.NetlinkPolicies {
pq.policies[pol.Name] = pol
}
for _, fam := range ctx.NetlinkFamilies {
if len(fam.Ops) == 0 {
// TODO: do something for these as well. These exist for a reason.
// Probably only send broadcast notifications (can bind and recvmsg).
continue
}
id := stringIdentifier(fam.Name)
ctx.fmt("resource genl_%v_family_id%v[int16]\n", id, autoSuffix)
ctx.fmt("type msghdr_%v%v[CMD, POLICY] msghdr_netlink[netlink_msg_t"+
"[genl_%v_family_id%v, genlmsghdr_t[CMD], POLICY]]\n", id, autoSuffix, id, autoSuffix)
ctx.fmt("syz_genetlink_get_family_id%v_%v(name ptr[in, string[\"%v\"]],"+
" fd sock_nl_generic) genl_%v_family_id%v\n\n", autoSuffix, id, fam.Name, id, autoSuffix)
for _, op := range fam.Ops {
policy := voidType
if op.Policy != "" {
policy = op.Policy + autoSuffix
pq.policyUsed(op.Policy)
}
name := ctx.uniqualize("netlink op", op.Name)
ctx.fmt("sendmsg%v_%v(fd sock_nl_generic,"+
" msg ptr[in, msghdr_%v%v[%v, %v]], f flags[send_flags])\n",
autoSuffix, name, id, autoSuffix, op.Name, policy)
ctx.noteInterface(&Interface{
Type: IfaceNetlinkOp,
Name: op.Name,
IdentifyingConst: op.Name,
Files: []string{fam.SourceFile},
Func: op.Func,
Access: op.Access,
AutoDescriptions: TristateYes,
})
}
for len(pq.pending) != 0 {
pol := pq.pending[0]
pq.pending = pq.pending[1:]
ctx.serializeNetlinkPolicy(pol, pq)
}
}
}
type policyQueue struct {
policies map[string]*NetlinkPolicy
pending []*NetlinkPolicy
}
func (pq *policyQueue) policyUsed(name string) {
if pol := pq.policies[name]; pol != nil {
delete(pq.policies, name)
pq.pending = append(pq.pending, pol)
}
}
func (ctx *context) serializeNetlinkPolicy(pol *NetlinkPolicy, pq *policyQueue) {
if len(pol.Attrs) == 0 {
ctx.fmt("type %v auto_todo\n", pol.Name+autoSuffix)
return
}
ctx.fmt("%v [\n", pol.Name+autoSuffix)
for _, attr := range pol.Attrs {
ctx.fmt("%v %v\n", attr.Name, ctx.nlattrType(attr, pq))
}
ctx.fmt("] [varlen]\n")
}
func (ctx *context) nlattrType(attr *NetlinkAttr, pq *policyQueue) string {
nlattr, typ := "nlattr", ""
switch attr.Kind {
case "NLA_BITFIELD32":
// TODO: Extract values from NLA_POLICY_BITFIELD32 macro.
typ = "int32"
case "NLA_MSECS":
typ = "int64"
case "NLA_FLAG":
typ = voidType
case "NLA_NESTED", "NLA_NESTED_ARRAY":
nlattr = "nlnest"
policy := "nl_generic_attr"
if attr.NestedPolicy != "" {
pq.policyUsed(attr.NestedPolicy)
policy = attr.NestedPolicy + autoSuffix
}
typ = fmt.Sprintf("array[%v]", policy)
if attr.Kind == "NLA_NESTED_ARRAY" {
typ = fmt.Sprintf("array[nlnest[0, %v]]", typ)
}
default:
field := &Field{
Name: strings.ToLower(attr.Name),
Type: ctx.netlinkType(attr),
}
typ = ctx.fieldType(field, nil, "", true)
}
return fmt.Sprintf("%v[%v, %v]", nlattr, attr.Name, typ)
}
func (ctx *context) netlinkType(attr *NetlinkAttr) *Type {
switch attr.Kind {
case "NLA_STRING", "NLA_NUL_STRING":
return &Type{
Buffer: &BufferType{
MaxSize: attr.MaxSize,
IsString: true,
IsNonTerminated: attr.Kind == "NLA_STRING",
},
}
case "NLA_BINARY", "NLA_UNSPEC", "":
if attr.Elem == nil {
switch attr.MaxSize {
case 1, 2, 4, 8:
attr.Kind = fmt.Sprintf("NLA_U%v", attr.MaxSize*8)
return ctx.netlinkTypeInt(attr)
}
minSize := 0
if attr.Kind != "NLA_BINARY" {
minSize = attr.MaxSize
}
return &Type{
Buffer: &BufferType{
MaxSize: attr.MaxSize,
MinSize: minSize,
},
}
}
elemSize := 1
switch {
case attr.Elem.Int != nil:
elemSize = attr.Elem.Int.ByteSize
case attr.Elem.Struct != "":
if str := ctx.structs[attr.Elem.Struct+autoSuffix]; str != nil {
elemSize = str.ByteSize
} else {
ctx.error("binary nlattr %v referenced non-existing struct %v",
attr.Name, attr.Elem.Struct)
}
default:
ctx.error("binary nlattr %v has unsupported elem type", attr.Name)
}
if attr.MaxSize%elemSize != 0 {
ctx.error("binary nlattr %v has odd size: %v, elem size %v",
attr.Name, attr.MaxSize, elemSize)
}
numElems := attr.MaxSize / elemSize
if numElems == 1 {
return attr.Elem
}
return &Type{
Array: &ArrayType{
Elem: attr.Elem,
MaxSize: numElems,
},
}
default:
return ctx.netlinkTypeInt(attr)
}
}
func (ctx *context) netlinkTypeInt(attr *NetlinkAttr) *Type {
size, be := 0, false
switch attr.Kind {
case "NLA_U8", "NLA_S8":
size = 1
case "NLA_U16", "NLA_S16":
size = 2
case "NLA_U32", "NLA_S32":
size = 4
case "NLA_U64", "NLA_S64", "NLA_SINT", "NLA_UINT":
size = 8
case "NLA_BE16":
size, be = 2, true
case "NLA_BE32":
size, be = 4, true
default:
panic(fmt.Sprintf("unhandled netlink attribute kind %v", attr.Kind))
}
return &Type{
Int: &IntType{
ByteSize: size,
isBigEndian: be,
},
}
}
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