Allow setting min eip 1559 base fees

consensus/misc/eip1559/eip1559.go

@@ -90,6 +90,11 @@ func CalcBaseFee(config *params.ChainConfig, parent *types.Header) *big.Int {
 		num.Div(num, denom.SetUint64(config.BaseFeeChangeDenominator()))
 		baseFee := num.Sub(parent.BaseFee, num)
 
-		return math.BigMax(baseFee, common.Big0)
+		lowerBound := common.Big0
+		if config.AstriaMinBaseFees != nil {
+			lowerBound = config.AstriaMinBaseFees.ValueAt(parent.Number.Uint64() + 1)
+		}
+
+		return math.BigMax(baseFee, lowerBound)
 	}
 }

genesis.json

@@ -21,7 +21,10 @@
         "astriaCelestiaInitialHeight": 2,
         "astriaCelestiaHeightVariance": 10,
         "astriaBridgeAddresses": [],
-        "astriaBridgeAllowedAssetDenom": "nria"
+        "astriaBridgeAllowedAssetDenom": "nria",
+        "astriaMinBaseFees": {
+            "1": "1000000000"
+        }
     },
     "difficulty": "10000000",
     "gasLimit": "8000000",

params/config.go

@@ -17,8 +17,10 @@
 package params
 
 import (
+	"encoding/json"
 	"fmt"
 	"math/big"
+	"sort"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
@@ -345,6 +347,7 @@ type ChainConfig struct {
 	AstriaCelestiaHeightVariance   uint32          `json:"astriaCelestiaHeightVariance,omitempty"`
 	AstriaBridgeAddresses          []hexutil.Bytes `json:"astriaBridgeAddresses,omitempty"`
 	AstriaBridgeAllowedAssetDenom  string          `json:"astriaBridgeAllowedAssetDenom,omitempty"`
+	AstriaMinBaseFees              *BaseFeeConfig  `json:"astriaMinBaseFees,omitempty"`
 }
 
 func (c *ChainConfig) AstriaExtraData() []byte {
@@ -368,6 +371,70 @@ func (c *ChainConfig) AstriaExtraData() []byte {
 	return extra
 }
 
+type BaseFeeConfig struct {
+	heights     map[uint64]*big.Int
+	current     *big.Int
+	initialized bool
+}
+
+func (c *BaseFeeConfig) ValueAt(height uint64) *big.Int {
+	c.init()
+	if value, exists := c.heights[height]; exists {
+		return value
+	}
+	return c.current
+}
+
+func (c *BaseFeeConfig) init() {
+	if c.initialized {
+		return
+	}
+
+	if len(c.heights) < 1 {
+		return
+	}
+
+	heights := []uint64{}
+	for k := range c.heights {
+		heights = append(heights, k)
+	}
+
+	sort.Slice(heights, func(i, j int) bool { return heights[i] < heights[j] })
+
+	c.current = big.NewInt(0)
+	lastHeight := heights[len(heights)-1]
+
+	for i := uint64(0); i <= lastHeight; i++ {
+		if _, exists := c.heights[i]; exists {
+			c.current = c.heights[i]
+		} else {
+			c.heights[i] = c.current
+		}
+	}
+
+	c.initialized = true
+}
+
+func (c BaseFeeConfig) MarshalJSON() ([]byte, error) {
+	distinctHeights := make(map[uint64]*big.Int)
+	for k, v := range c.heights {
+		if _, exists := distinctHeights[k]; !exists {
+			distinctHeights[k] = v
+		}
+	}
+	return json.Marshal(distinctHeights)
+}
+
+func (c *BaseFeeConfig) UnmarshalJSON(data []byte) error {
+	if err := json.Unmarshal(data, &c.heights); err != nil {
+		return err
+	}
+
+	c.init()
+
+	return nil
+}
+
 // EthashConfig is the consensus engine configs for proof-of-work based sealing.
 type EthashConfig struct{}